C stdlib.h library function: The stdlib.h header defines four variable types, several macros, and various functions for performing general functions. It can be derived as a “standard input-output library“.
C stdlib.h library function
List of inbuilt C functions in <stdlib.h>
| Function | Description |
|---|---|
| malloc( ) | used to allocate space in memory during the execution of the program |
| calloc( ) | It is also like the malloc () function. But calloc () initializes the allocated memory to zero. But, malloc() doesn’t |
| realloc( ) | modifies the allocated memory size by malloc( ) and calloc( ) functions to new size |
| free( ) | It frees the allocated memory by malloc (), calloc (), realloc() functions and returns the memory to the system |
| abs( ) | It returns the absolute value of an integer. The absolute value of a number is always positive. Only integer values are supported in C. |
| div( ) | This function performs a division operation |
| abort( ) | It terminates the C program |
| exit( ) | This function terminates the program and does not return any value |
| system() | It is used to execute commands outside the C program |
| atoi() | Converts string to int |
| atol() | Converts string to long |
| atof() | Converts string to float |
| strtod() | Converts string to double |
| strtol() | Converts string to long |
| getenv() | This function gets the current value of the environment variable |
| setenv() | This function sets the value for the environment variable |
| putenv() | This function modifies the value for an environment variable |
| perror() | This function displays the most recent error that happened during a library function call |
| rand() | This function returns the random integer numbers |
| delay() | This function suspends the execution of the program for a particular time |