Functions in stdlib h header file

This function is also like malloc function. But calloc initializes the allocated memory to zero. This function modifies the allocated memory size by malloc and calloc functions to new size.

This function frees the allocated memory by malloc , calloc , realloc functions and returns the memory to the system. This function returns the absolute value of an integer. The absolute value of a number is always positive. Only integer values are supported in C. This function terminates the program and does not return any value. This function is used to execute commands outside the C program. This function gets the current value of the environment variable.

This function displays most recent error that happened during library function call. Converts the string pointed to, by the argument str to a floating-point number type double. Converts the string pointed to, by the argument str to an unsigned long integer type unsigned long int.

Deallocates the memory previously allocated by a call to calloc, malloc, or realloc. Attempts to resize the memory block pointed to by ptr that was previously allocated with a call to malloc or calloc. Searches for the environment string pointed to by name and returns the associated value to the string. The command specified by string is passed to the host environment to be executed by the command processor. Converts the string of multibyte characters pointed to by the argument str to the array pointed to by pwcs.

Converts the codes stored in the array pwcs to multibyte characters and stores them in the string str. Examines the code which corresponds to a multibyte character given by the argument wchar. Nishant Malik. Asif Hussain.