getenv

Returns an environment value.

Syntax

   #include <stdlib.h>

   char *getenv (const char *name);

Parameters

name: A pointer to a string of characters to match in the environment list.

Return Values

<>NULL: A pointer to the value portion of a name=value string is returned.
NULL: A matching name was not found, and errno is not modified.
NULL + errno: An error occurred, and errno is set to indicate the error condition.

Description

The getenv() function takes a string, name, and searches for a matching name in the environment list (in environ) associated with the calling process.

If a match to name is found, getenv() returns a pointer to the value portion of that string. The value is terminated by a null character. If a matching name is not found, getenv() returns a NULL pointer but does not modify the current value of errno.

The environment list contains strings in the form name=value. If more than one string has the same name, getenv() returns the value for the first matching name found. The length of name is limited by {ARG_MAX} as defined in <limits.h>.

Implementation Considerations

Refer to the EFAULT error description below.

Errors

If an error occurs, errno is set to the following value:

`EFAULT`	CAUSE	The system detected a NULL or bad address in attempting to use the `name` parameter or while dereferencing `environ` and traversing the process's environment list.
	ACTION	Check to see if the pointer is correctly initialized or if the environment list is corrupted.

getenv

Technical documentation

» Table of Contents

» Index