C Programming Standard Library Functions

In this tutorial, we will learn about standard library functions of C programming language. Here, we will discuss about function prototype, function input parameters and return type with sample C program. Currently, it contains descriptions of most commonly used C library functions in stdio.h, stdlib.h, string.h, ctype.h, math.h, errno.h and assert.h header files.

A header file in C programming language is a file with .h extension which contains a set of function declarations and macro definitions which can be shared across multiple program files. C language provides a set of in build header files which contains commonly used utility functions and macros.

The function's prototype and definitions are present in their respective header files, and we must include it in our program to access library function.

For Example
To use strcpy() function in our program, we must include <string.h> header file.

Advantages of C Standard Library Functions
  • It reduces application development time as you don't have to write code for functionalities provided by standard library functions. t saves considerable development time.

  • Reliable and time tested code. Standard library functions are used everywhere from long time. These functions have been tested rigorous several times.

  • Standard library functions are optimized for faster execution and for using less memory space.