Contents
About ................................................................................................................................................................................... 1
Chapter 1: Getting started with C Language .................................................................................................. 2
Section 1.1: Hello World ................................................................................................................................................. 2
Section 1.2: Original "Hello, World!" in K&R C .............................................................................................................. 4
Chapter 2: Comments ................................................................................................................................................. 6
Section 2.1: Commenting using the preprocessor ...................................................................................................... 6
Section 2.2: /* */ delimited comments ........................................................................................................................ 6
Section 2.3: // delimited comments ............................................................................................................................ 7
Section 2.4: Possible pitfall due to trigraphs .............................................................................................................. 7
Chapter 3: Data Types ............................................................................................................................................... 9
Section 3.1: Interpreting Declarations .......................................................................................................................... 9
Section 3.2: Fixed Width Integer Types (since C99) ................................................................................................. 11
Section 3.3: Integer types and constants .................................................................................................................. 11
Section 3.4: Floating Point Constants ........................................................................................................................ 12
Section 3.5: String Literals .......................................................................................................................................... 13
Chapter 4: Operators ............................................................................................................................................... 14
Section 4.1: Relational Operators ............................................................................................................................... 14
Section 4.2: Conditional Operator/Ternary Operator ............................................................................................. 15
Section 4.3: Bitwise Operators ................................................................................................................................... 16
Section 4.4: Short circuit behavior of logical operators .......................................................................................... 18
Section 4.5: Comma Operator ................................................................................................................................... 19
Section 4.6: Arithmetic Operators .............................................................................................................................. 19
Section 4.7: Access Operators ................................................................................................................................... 22
Section 4.8: sizeof Operator ....................................................................................................................................... 24
Section 4.9: Cast Operator ......................................................................................................................................... 24
Section 4.10: Function Call Operator ......................................................................................................................... 24
Section 4.11: Increment / Decrement ......................................................................................................................... 25
Section 4.12: Assignment Operators .......................................................................................................................... 25
Section 4.13: Logical Operators .................................................................................................................................. 26
Section 4.14: Pointer Arithmetic .................................................................................................................................. 27
Section 4.15: _Alignof .................................................................................................................................................. 28
Chapter 5: Boolean .................................................................................................................................................... 30
Section 5.1: Using stdbool.h ........................................................................................................................................ 30
Section 5.2: Using #define .......................................................................................................................................... 30
Section 5.3: Using the Intrinsic (built-in) Type _Bool ............................................................................................... 31
Section 5.4: Integers and pointers in Boolean expressions .................................................................................... 31
Section 5.5: Defining a bool type using typedef ...................................................................................................... 32
Chapter 6: Strings ....................................................................................................................................................... 33
Section 6.1: Tokenisation: strtok(), strtok_r() and strtok_s() .................................................................................. 33
Section 6.2: String literals ........................................................................................................................................... 35
Section 6.3: Calculate the Length: strlen() ................................................................................................................ 36
Section 6.4: Basic introduction to strings .................................................................................................................. 37
Section 6.5: Copying strings ....................................................................................................................................... 37
Section 6.6: Iterating Over the Characters in a String ............................................................................................. 40
Section 6.7: Creating Arrays of Strings ..................................................................................................................... 41
Section 6.8: Convert Strings to Number: atoi(), atof() (dangerous, don't use them) ........................................... 41
Section 6.9: string formatted data read/write ......................................................................................................... 42
, Section 6.10: Find first/last occurrence of a specific character: strchr(), strrchr() ............................................... 43
Section 6.11: Copy and Concatenation: strcpy(), strcat() ........................................................................................ 44
Section 6.12: Comparsion: strcmp(), strncmp(), strcasecmp(), strncasecmp() .................................................... 45
Section 6.13: Safely convert Strings to Number: strtoX functions .......................................................................... 47
Section 6.14: strspn and strcspn ................................................................................................................................. 48
Chapter 7: Literals for numbers, characters and strings ...................................................................... 50
Section 7.1: Floating point literals ............................................................................................................................... 50
Section 7.2: String literals ........................................................................................................................................... 50
Section 7.3: Character literals .................................................................................................................................... 50
Section 7.4: Integer literals ......................................................................................................................................... 51
Chapter 8: Compound Literals ............................................................................................................................. 53
Section 8.1: Definition/Initialisation of Compound Literals ...................................................................................... 53
Chapter 9: Bit-fields .................................................................................................................................................. 55
Section 9.1: Bit-fields .................................................................................................................................................... 55
Section 9.2: Using bit-fields as small integers .......................................................................................................... 56
Section 9.3: Bit-field alignment .................................................................................................................................. 56
Section 9.4: Don'ts for bit-fields ................................................................................................................................. 57
Section 9.5: When are bit-fields useful? .................................................................................................................... 58
Chapter 10: Arrays ...................................................................................................................................................... 60
Section 10.1: Declaring and initializing an array ....................................................................................................... 60
Section 10.2: Iterating through an array eciently and row-major order ............................................................ 61
Section 10.3: Array length ........................................................................................................................................... 62
Section 10.4: Passing multidimensional arrays to a function ................................................................................. 63
Section 10.5: Multi-dimensional arrays ...................................................................................................................... 64
Section 10.6: Define array and access array element ............................................................................................. 67
Section 10.7: Clearing array contents (zeroing) ....................................................................................................... 67
Section 10.8: Setting values in arrays ........................................................................................................................ 68
Section 10.9: Allocate and zero-initialize an array with user defined size ............................................................. 68
Section 10.10: Iterating through an array using pointers ........................................................................................ 69
Chapter 11: Linked lists ............................................................................................................................................. 71
Section 11.1: A doubly linked list .................................................................................................................................. 71
Section 11.2: Reversing a linked list ............................................................................................................................ 73
Section 11.3: Inserting a node at the nth position ..................................................................................................... 75
Section 11.4: Inserting a node at the beginning of a singly linked list .................................................................... 76
Chapter 12: Enumerations ...................................................................................................................................... 79
Section 12.1: Simple Enumeration ............................................................................................................................... 79
Section 12.2: enumeration constant without typename .......................................................................................... 80
Section 12.3: Enumeration with duplicate value ....................................................................................................... 80
Section 12.4: Typedef enum ....................................................................................................................................... 81
Chapter 13: Structs ..................................................................................................................................................... 83
Section 13.1: Flexible Array Members ......................................................................................................................... 83
Section 13.2: Typedef Structs ..................................................................................................................................... 85
Section 13.3: Pointers to structs .................................................................................................................................. 86
Section 13.4: Passing structs to functions ................................................................................................................. 88
Section 13.5: Object-based programming using structs ......................................................................................... 89
Section 13.6: Simple data structures .......................................................................................................................... 91
Chapter 14: Standard Math ................................................................................................................................... 93
Section 14.1: Power functions - pow(), powf(), powl() .............................................................................................. 93
Section 14.2: Double precision floating-point remainder: fmod() .......................................................................... 94
, Section 14.3: Single precision and long double precision floating-point remainder: fmodf(), fmodl() ............... 94
Chapter 15: Iteration Statements/Loops: for, while, do-while ............................................................ 96
Section 15.1: For loop ................................................................................................................................................... 96
Section 15.2: Loop Unrolling and Du's Device ........................................................................................................ 96
Section 15.3: While loop ............................................................................................................................................... 97
Section 15.4: Do-While loop ........................................................................................................................................ 97
Section 15.5: Structure and flow of control in a for loop ......................................................................................... 98
Section 15.6: Infinite Loops .......................................................................................................................................... 99
Chapter 16: Selection Statements .................................................................................................................... 100
Section 16.1: if () Statements ..................................................................................................................................... 100
Section 16.2: Nested if()...else VS if()..else Ladder .................................................................................................. 100
Section 16.3: switch () Statements ........................................................................................................................... 102
Section 16.4: if () ... else statements and syntax ..................................................................................................... 104
Section 16.5: if()...else Ladder Chaining two or more if () ... else statements ....................................................... 104
Chapter 17: Initialization ........................................................................................................................................ 105
Section 17.1: Initialization of Variables in C .............................................................................................................. 105
Section 17.2: Using designated initializers ............................................................................................................... 106
Section 17.3: Initializing structures and arrays of structures ................................................................................ 108
Chapter 18: Declaration vs Definition ............................................................................................................ 110
Section 18.1: Understanding Declaration and Definition ....................................................................................... 110
Chapter 19: Command-line arguments ......................................................................................................... 111
Section 19.1: Print the arguments to a program and convert to integer values ................................................. 111
Section 19.2: Printing the command line arguments ............................................................................................. 111
Section 19.3: Using GNU getopt tools ...................................................................................................................... 112
Chapter 20: Files and I/O streams .................................................................................................................. 115
Section 20.1: Open and write to file ......................................................................................................................... 115
Section 20.2: Run process ........................................................................................................................................ 116
Section 20.3: fprintf ................................................................................................................................................... 116
Section 20.4: Get lines from a file using getline() .................................................................................................. 116
Section 20.5: fscanf() ................................................................................................................................................ 120
Section 20.6: Read lines from a file ......................................................................................................................... 121
Section 20.7: Open and write to a binary file ......................................................................................................... 122
Chapter 21: Formatted Input/Output ............................................................................................................. 124
Section 21.1: Conversion Specifiers for printing ...................................................................................................... 124
Section 21.2: The printf() Function ........................................................................................................................... 125
Section 21.3: Printing format flags ........................................................................................................................... 125
Section 21.4: Printing the Value of a Pointer to an Object .................................................................................... 126
Section 21.5: Printing the Dierence of the Values of two Pointers to an Object ............................................... 127
Section 21.6: Length modifiers ................................................................................................................................. 128
Chapter 22: Pointers ................................................................................................................................................ 129
Section 22.1: Introduction ......................................................................................................................................... 129
Section 22.2: Common errors .................................................................................................................................. 131
Section 22.3: Dereferencing a Pointer .................................................................................................................... 134
Section 22.4: Dereferencing a Pointer to a struct .................................................................................................. 134
Section 22.5: Const Pointers ..................................................................................................................................... 135
Section 22.6: Function pointers ................................................................................................................................ 138
Section 22.7: Polymorphic behaviour with void pointers ...................................................................................... 139
Section 22.8: Address-of Operator ( & ) ................................................................................................................. 140
Section 22.9: Initializing Pointers ............................................................................................................................. 140
, Section 22.10: Pointer to Pointer .............................................................................................................................. 141
Section 22.11: void* pointers as arguments and return values to standard functions ....................................... 141
Section 22.12: Same Asterisk, Dierent Meanings ................................................................................................. 142
Chapter 23: Sequence points .............................................................................................................................. 144
Section 23.1: Unsequenced expressions .................................................................................................................. 144
Section 23.2: Sequenced expressions ..................................................................................................................... 144
Section 23.3: Indeterminately sequenced expressions ......................................................................................... 145
Chapter 24: Function Pointers ........................................................................................................................... 146
Section 24.1: Introduction .......................................................................................................................................... 146
Section 24.2: Returning Function Pointers from a Function ................................................................................. 146
Section 24.3: Best Practices ..................................................................................................................................... 147
Section 24.4: Assigning a Function Pointer ............................................................................................................. 149
Section 24.5: Mnemonic for writing function pointers ........................................................................................... 149
Section 24.6: Basics ................................................................................................................................................... 150
Chapter 25: Function Parameters .................................................................................................................... 152
Section 25.1: Parameters are passed by value ...................................................................................................... 152
Section 25.2: Passing in Arrays to Functions .......................................................................................................... 152
Section 25.3: Order of function parameter execution ........................................................................................... 153
Section 25.4: Using pointer parameters to return multiple values ...................................................................... 153
Section 25.5: Example of function returning struct containing values with error codes ................................... 154
Chapter 26: Pass 2D-arrays to functions ..................................................................................................... 156
Section 26.1: Pass a 2D-array to a function ........................................................................................................... 156
Section 26.2: Using flat arrays as 2D arrays .......................................................................................................... 162
Chapter 27: Error handling .................................................................................................................................. 163
Section 27.1: errno ..................................................................................................................................................... 163
Section 27.2: strerror ................................................................................................................................................. 163
Section 27.3: perror ................................................................................................................................................... 163
Chapter 28: Undefined behavior ...................................................................................................................... 165
Section 28.1: Dereferencing a pointer to variable beyond its lifetime ................................................................. 165
Section 28.2: Copying overlapping memory .......................................................................................................... 165
Section 28.3: Signed integer overflow ..................................................................................................................... 166
Section 28.4: Use of an uninitialized variable ......................................................................................................... 167
Section 28.5: Data race ............................................................................................................................................ 168
Section 28.6: Read value of pointer that was freed .............................................................................................. 169
Section 28.7: Using incorrect format specifier in printf ......................................................................................... 170
Section 28.8: Modify string literal ............................................................................................................................ 170
Section 28.9: Passing a null pointer to printf %s conversion ................................................................................ 170
Section 28.10: Modifying any object more than once between two sequence points ....................................... 171
Section 28.11: Freeing memory twice ...................................................................................................................... 172
Section 28.12: Bit shifting using negative counts or beyond the width of the type ............................................ 172
Section 28.13: Returning from a function that's declared with `_Noreturn` or `noreturn` function specifier
............................................................................................................................................................................. 173
Section 28.14: Accessing memory beyond allocated chunk ................................................................................. 174
Section 28.15: Modifying a const variable using a pointer .................................................................................... 174
Section 28.16: Reading an uninitialized object that is not backed by memory .................................................. 175
Section 28.17: Addition or subtraction of pointer not properly bounded ............................................................ 175
Section 28.18: Dereferencing a null pointer ............................................................................................................ 175
Section 28.19: Using ush on an input stream ...................................................................................................... 176
Section 28.20: Inconsistent linkage of identifiers ................................................................................................... 176
Section 28.21: Missing return statement in value returning function ................................................................... 177
About ................................................................................................................................................................................... 1
Chapter 1: Getting started with C Language .................................................................................................. 2
Section 1.1: Hello World ................................................................................................................................................. 2
Section 1.2: Original "Hello, World!" in K&R C .............................................................................................................. 4
Chapter 2: Comments ................................................................................................................................................. 6
Section 2.1: Commenting using the preprocessor ...................................................................................................... 6
Section 2.2: /* */ delimited comments ........................................................................................................................ 6
Section 2.3: // delimited comments ............................................................................................................................ 7
Section 2.4: Possible pitfall due to trigraphs .............................................................................................................. 7
Chapter 3: Data Types ............................................................................................................................................... 9
Section 3.1: Interpreting Declarations .......................................................................................................................... 9
Section 3.2: Fixed Width Integer Types (since C99) ................................................................................................. 11
Section 3.3: Integer types and constants .................................................................................................................. 11
Section 3.4: Floating Point Constants ........................................................................................................................ 12
Section 3.5: String Literals .......................................................................................................................................... 13
Chapter 4: Operators ............................................................................................................................................... 14
Section 4.1: Relational Operators ............................................................................................................................... 14
Section 4.2: Conditional Operator/Ternary Operator ............................................................................................. 15
Section 4.3: Bitwise Operators ................................................................................................................................... 16
Section 4.4: Short circuit behavior of logical operators .......................................................................................... 18
Section 4.5: Comma Operator ................................................................................................................................... 19
Section 4.6: Arithmetic Operators .............................................................................................................................. 19
Section 4.7: Access Operators ................................................................................................................................... 22
Section 4.8: sizeof Operator ....................................................................................................................................... 24
Section 4.9: Cast Operator ......................................................................................................................................... 24
Section 4.10: Function Call Operator ......................................................................................................................... 24
Section 4.11: Increment / Decrement ......................................................................................................................... 25
Section 4.12: Assignment Operators .......................................................................................................................... 25
Section 4.13: Logical Operators .................................................................................................................................. 26
Section 4.14: Pointer Arithmetic .................................................................................................................................. 27
Section 4.15: _Alignof .................................................................................................................................................. 28
Chapter 5: Boolean .................................................................................................................................................... 30
Section 5.1: Using stdbool.h ........................................................................................................................................ 30
Section 5.2: Using #define .......................................................................................................................................... 30
Section 5.3: Using the Intrinsic (built-in) Type _Bool ............................................................................................... 31
Section 5.4: Integers and pointers in Boolean expressions .................................................................................... 31
Section 5.5: Defining a bool type using typedef ...................................................................................................... 32
Chapter 6: Strings ....................................................................................................................................................... 33
Section 6.1: Tokenisation: strtok(), strtok_r() and strtok_s() .................................................................................. 33
Section 6.2: String literals ........................................................................................................................................... 35
Section 6.3: Calculate the Length: strlen() ................................................................................................................ 36
Section 6.4: Basic introduction to strings .................................................................................................................. 37
Section 6.5: Copying strings ....................................................................................................................................... 37
Section 6.6: Iterating Over the Characters in a String ............................................................................................. 40
Section 6.7: Creating Arrays of Strings ..................................................................................................................... 41
Section 6.8: Convert Strings to Number: atoi(), atof() (dangerous, don't use them) ........................................... 41
Section 6.9: string formatted data read/write ......................................................................................................... 42
, Section 6.10: Find first/last occurrence of a specific character: strchr(), strrchr() ............................................... 43
Section 6.11: Copy and Concatenation: strcpy(), strcat() ........................................................................................ 44
Section 6.12: Comparsion: strcmp(), strncmp(), strcasecmp(), strncasecmp() .................................................... 45
Section 6.13: Safely convert Strings to Number: strtoX functions .......................................................................... 47
Section 6.14: strspn and strcspn ................................................................................................................................. 48
Chapter 7: Literals for numbers, characters and strings ...................................................................... 50
Section 7.1: Floating point literals ............................................................................................................................... 50
Section 7.2: String literals ........................................................................................................................................... 50
Section 7.3: Character literals .................................................................................................................................... 50
Section 7.4: Integer literals ......................................................................................................................................... 51
Chapter 8: Compound Literals ............................................................................................................................. 53
Section 8.1: Definition/Initialisation of Compound Literals ...................................................................................... 53
Chapter 9: Bit-fields .................................................................................................................................................. 55
Section 9.1: Bit-fields .................................................................................................................................................... 55
Section 9.2: Using bit-fields as small integers .......................................................................................................... 56
Section 9.3: Bit-field alignment .................................................................................................................................. 56
Section 9.4: Don'ts for bit-fields ................................................................................................................................. 57
Section 9.5: When are bit-fields useful? .................................................................................................................... 58
Chapter 10: Arrays ...................................................................................................................................................... 60
Section 10.1: Declaring and initializing an array ....................................................................................................... 60
Section 10.2: Iterating through an array eciently and row-major order ............................................................ 61
Section 10.3: Array length ........................................................................................................................................... 62
Section 10.4: Passing multidimensional arrays to a function ................................................................................. 63
Section 10.5: Multi-dimensional arrays ...................................................................................................................... 64
Section 10.6: Define array and access array element ............................................................................................. 67
Section 10.7: Clearing array contents (zeroing) ....................................................................................................... 67
Section 10.8: Setting values in arrays ........................................................................................................................ 68
Section 10.9: Allocate and zero-initialize an array with user defined size ............................................................. 68
Section 10.10: Iterating through an array using pointers ........................................................................................ 69
Chapter 11: Linked lists ............................................................................................................................................. 71
Section 11.1: A doubly linked list .................................................................................................................................. 71
Section 11.2: Reversing a linked list ............................................................................................................................ 73
Section 11.3: Inserting a node at the nth position ..................................................................................................... 75
Section 11.4: Inserting a node at the beginning of a singly linked list .................................................................... 76
Chapter 12: Enumerations ...................................................................................................................................... 79
Section 12.1: Simple Enumeration ............................................................................................................................... 79
Section 12.2: enumeration constant without typename .......................................................................................... 80
Section 12.3: Enumeration with duplicate value ....................................................................................................... 80
Section 12.4: Typedef enum ....................................................................................................................................... 81
Chapter 13: Structs ..................................................................................................................................................... 83
Section 13.1: Flexible Array Members ......................................................................................................................... 83
Section 13.2: Typedef Structs ..................................................................................................................................... 85
Section 13.3: Pointers to structs .................................................................................................................................. 86
Section 13.4: Passing structs to functions ................................................................................................................. 88
Section 13.5: Object-based programming using structs ......................................................................................... 89
Section 13.6: Simple data structures .......................................................................................................................... 91
Chapter 14: Standard Math ................................................................................................................................... 93
Section 14.1: Power functions - pow(), powf(), powl() .............................................................................................. 93
Section 14.2: Double precision floating-point remainder: fmod() .......................................................................... 94
, Section 14.3: Single precision and long double precision floating-point remainder: fmodf(), fmodl() ............... 94
Chapter 15: Iteration Statements/Loops: for, while, do-while ............................................................ 96
Section 15.1: For loop ................................................................................................................................................... 96
Section 15.2: Loop Unrolling and Du's Device ........................................................................................................ 96
Section 15.3: While loop ............................................................................................................................................... 97
Section 15.4: Do-While loop ........................................................................................................................................ 97
Section 15.5: Structure and flow of control in a for loop ......................................................................................... 98
Section 15.6: Infinite Loops .......................................................................................................................................... 99
Chapter 16: Selection Statements .................................................................................................................... 100
Section 16.1: if () Statements ..................................................................................................................................... 100
Section 16.2: Nested if()...else VS if()..else Ladder .................................................................................................. 100
Section 16.3: switch () Statements ........................................................................................................................... 102
Section 16.4: if () ... else statements and syntax ..................................................................................................... 104
Section 16.5: if()...else Ladder Chaining two or more if () ... else statements ....................................................... 104
Chapter 17: Initialization ........................................................................................................................................ 105
Section 17.1: Initialization of Variables in C .............................................................................................................. 105
Section 17.2: Using designated initializers ............................................................................................................... 106
Section 17.3: Initializing structures and arrays of structures ................................................................................ 108
Chapter 18: Declaration vs Definition ............................................................................................................ 110
Section 18.1: Understanding Declaration and Definition ....................................................................................... 110
Chapter 19: Command-line arguments ......................................................................................................... 111
Section 19.1: Print the arguments to a program and convert to integer values ................................................. 111
Section 19.2: Printing the command line arguments ............................................................................................. 111
Section 19.3: Using GNU getopt tools ...................................................................................................................... 112
Chapter 20: Files and I/O streams .................................................................................................................. 115
Section 20.1: Open and write to file ......................................................................................................................... 115
Section 20.2: Run process ........................................................................................................................................ 116
Section 20.3: fprintf ................................................................................................................................................... 116
Section 20.4: Get lines from a file using getline() .................................................................................................. 116
Section 20.5: fscanf() ................................................................................................................................................ 120
Section 20.6: Read lines from a file ......................................................................................................................... 121
Section 20.7: Open and write to a binary file ......................................................................................................... 122
Chapter 21: Formatted Input/Output ............................................................................................................. 124
Section 21.1: Conversion Specifiers for printing ...................................................................................................... 124
Section 21.2: The printf() Function ........................................................................................................................... 125
Section 21.3: Printing format flags ........................................................................................................................... 125
Section 21.4: Printing the Value of a Pointer to an Object .................................................................................... 126
Section 21.5: Printing the Dierence of the Values of two Pointers to an Object ............................................... 127
Section 21.6: Length modifiers ................................................................................................................................. 128
Chapter 22: Pointers ................................................................................................................................................ 129
Section 22.1: Introduction ......................................................................................................................................... 129
Section 22.2: Common errors .................................................................................................................................. 131
Section 22.3: Dereferencing a Pointer .................................................................................................................... 134
Section 22.4: Dereferencing a Pointer to a struct .................................................................................................. 134
Section 22.5: Const Pointers ..................................................................................................................................... 135
Section 22.6: Function pointers ................................................................................................................................ 138
Section 22.7: Polymorphic behaviour with void pointers ...................................................................................... 139
Section 22.8: Address-of Operator ( & ) ................................................................................................................. 140
Section 22.9: Initializing Pointers ............................................................................................................................. 140
, Section 22.10: Pointer to Pointer .............................................................................................................................. 141
Section 22.11: void* pointers as arguments and return values to standard functions ....................................... 141
Section 22.12: Same Asterisk, Dierent Meanings ................................................................................................. 142
Chapter 23: Sequence points .............................................................................................................................. 144
Section 23.1: Unsequenced expressions .................................................................................................................. 144
Section 23.2: Sequenced expressions ..................................................................................................................... 144
Section 23.3: Indeterminately sequenced expressions ......................................................................................... 145
Chapter 24: Function Pointers ........................................................................................................................... 146
Section 24.1: Introduction .......................................................................................................................................... 146
Section 24.2: Returning Function Pointers from a Function ................................................................................. 146
Section 24.3: Best Practices ..................................................................................................................................... 147
Section 24.4: Assigning a Function Pointer ............................................................................................................. 149
Section 24.5: Mnemonic for writing function pointers ........................................................................................... 149
Section 24.6: Basics ................................................................................................................................................... 150
Chapter 25: Function Parameters .................................................................................................................... 152
Section 25.1: Parameters are passed by value ...................................................................................................... 152
Section 25.2: Passing in Arrays to Functions .......................................................................................................... 152
Section 25.3: Order of function parameter execution ........................................................................................... 153
Section 25.4: Using pointer parameters to return multiple values ...................................................................... 153
Section 25.5: Example of function returning struct containing values with error codes ................................... 154
Chapter 26: Pass 2D-arrays to functions ..................................................................................................... 156
Section 26.1: Pass a 2D-array to a function ........................................................................................................... 156
Section 26.2: Using flat arrays as 2D arrays .......................................................................................................... 162
Chapter 27: Error handling .................................................................................................................................. 163
Section 27.1: errno ..................................................................................................................................................... 163
Section 27.2: strerror ................................................................................................................................................. 163
Section 27.3: perror ................................................................................................................................................... 163
Chapter 28: Undefined behavior ...................................................................................................................... 165
Section 28.1: Dereferencing a pointer to variable beyond its lifetime ................................................................. 165
Section 28.2: Copying overlapping memory .......................................................................................................... 165
Section 28.3: Signed integer overflow ..................................................................................................................... 166
Section 28.4: Use of an uninitialized variable ......................................................................................................... 167
Section 28.5: Data race ............................................................................................................................................ 168
Section 28.6: Read value of pointer that was freed .............................................................................................. 169
Section 28.7: Using incorrect format specifier in printf ......................................................................................... 170
Section 28.8: Modify string literal ............................................................................................................................ 170
Section 28.9: Passing a null pointer to printf %s conversion ................................................................................ 170
Section 28.10: Modifying any object more than once between two sequence points ....................................... 171
Section 28.11: Freeing memory twice ...................................................................................................................... 172
Section 28.12: Bit shifting using negative counts or beyond the width of the type ............................................ 172
Section 28.13: Returning from a function that's declared with `_Noreturn` or `noreturn` function specifier
............................................................................................................................................................................. 173
Section 28.14: Accessing memory beyond allocated chunk ................................................................................. 174
Section 28.15: Modifying a const variable using a pointer .................................................................................... 174
Section 28.16: Reading an uninitialized object that is not backed by memory .................................................. 175
Section 28.17: Addition or subtraction of pointer not properly bounded ............................................................ 175
Section 28.18: Dereferencing a null pointer ............................................................................................................ 175
Section 28.19: Using ush on an input stream ...................................................................................................... 176
Section 28.20: Inconsistent linkage of identifiers ................................................................................................... 176
Section 28.21: Missing return statement in value returning function ................................................................... 177
