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clearenv()

Clear the environment

Synopsis:

#include <stdlib.h>

int clearenv( void );

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The clearenv() function clears the environment area; no environment variables are defined immediately after the clearenv() call.

Note that clearenv() clears the following environment variables, which may then affect the operation of other library functions such as spawnp():

• PATH
• SHELL
• TERM
• TERMINFO
• LINES
• COLUMNS
• TZ

Returns:

0

Success.

-1

An error occurred (errno is set).

Errors:

ENOMEM

Not enough memory to allocate a control structure.

Examples:

Clear the entire environment and set up a new TZ environment variable:

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

int main( void )
{
    if( clearenv() != 0 ) {
        puts( "Unable to clear the environment" );
        return EXIT_FAILURE;
    }

    setenv( "TZ", "EST5EDT", 0 );
    
    return EXIT_SUCCESS;
}

Classification:

QNX 4

Safety:
Cancellation point	No
Interrupt handler	No
Signal handler	No
Thread	Yes

Caveats:

The clearenv() function manipulates the environment pointed to by the global environ variable.

See also:

environ, errno, execl(), execle(), execlp(), execlpe(), execv(), execve(), execvp(), execvpe(), getenv(), putenv(), searchenv(), setenv(), spawn(), spawnl(), spawnle(), spawnlp(), spawnlpe(), spawnp(), spawnv(), spawnve(), spawnvp(), spawnvpe(), system(), unsetenv()

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