C library function - getenv()


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Description

The C library function char *getenv(const char *name) searches for the environment string pointed to by name and returns the associated value to the string.

Declaration

Following is the declaration for getenv() function.

char *getenv(const char *name)

Parameters

  • name − This is the C string containing the name of the requested variable.

Return Value

This function returns a null-terminated string with the value of the requested environment variable, or NULL if that environment variable does not exist.

Example

The following example shows the usage of getenv() function.

Live Demo
#include <stdio.h>
#include <stdlib.h>

int main () {
   printf("PATH : %s\n", getenv("PATH"));
   printf("HOME : %s\n", getenv("HOME"));
   printf("ROOT : %s\n", getenv("ROOT"));

   return(0);
}

Let us compile and run the above program that will produce the following result −

PATH : /sbin:/usr/sbin:/bin:/usr/bin:/usr/local/bin
HOME : /
ROOT : (null)

stdlib_h.htm

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