C language getenv() function: used to obtain the string in the current environment

Function name : getenv

Header file : <stdlib.h>

Function prototype : char *getenv(char *name);

Function : used to get the string in the current environment

Parameter : char *name is the environment variable name

Return value : Returns the given environment variable value. If the specified environment variable is not defined in the environment, NULL is returned;

Program example : Use this function to obtain the first address of the environment string named COMSPEC and display it.

 #include<stdio.h>#include<stdlib.h>#include<string.h>intmain(void){char*s=getenv(COMSPEC);printf(Commandprocessor:%sn,s);return0;}

Running results

 Commandprocessor:C:Windowssystem32cmd.exe