getenv - cppreference.com

##### cppreference.com

##### Search

Create account

##### Namespaces

- Page
- Discussion

##### Variants

##### Views

- View
- Edit
- History

##### Actions

# getenv

From cppreference.com
< c‎ | program

Defined in header `<stdlib.h>` |  |
const char *getenv( const char *env_var ); |  |

Searches for an environmental variable with name `env_var` in the host-specified environment list and returns information associated with it. The set of environmental variables and methods of altering it are implementation-defined.

### [edit] Parameters

env_var | - | null-terminated character string identifying the name of the environmental variable to look for

### [edit] Return value

character string identifying the value of the environmental variable or NULL if such variable is not found.

### [edit] Example

Run this code

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

    int main(void)
    {
        char * env_p;
        env_p = getenv ("PATH");
        if (env_p == NULL)
        {
           printf("getenv() failed in file %s at line # %d", __FILE__,__LINE__);
           exit(1);
        }
        printf("PATH = %s\n", env_p);

        env_p = getenv ("HOME");
        printf("HOME = %s\n", env_p);

        env_p = getenv ("PWD");
        printf("PWD = %s\n", env_p);

        env_p = getenv ("LD_LIBRARY_PATH");
        printf("LD_LIBRARY_PATH = %s\n", env_p);

        env_p = getenv ("LANG");
        printf("LANG = %s\n", env_p);

        env_p = getenv ("LC_ALL");
        printf("LC_ALL = %s\n", env_p);

        env_p = getenv ("TZ");
        printf("TZ = %s\n", env_p);

        return 0;
    }

Output:

    PATH = /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
    HOME = /home/sandbox
    PWD = /tmp/1398126808-1302695176
    LD_LIBRARY_PATH = /usr/local/lib
    LANG = en_US.UTF-8
    LC_ALL = C
    TZ = (null)

### [edit] See also

C++ documentation for getenv

Retrieved from "http://en.cppreference.com/mwiki/index.php?title=c/program/getenv&oldid=69739"