bionic (3) unsetenv.3posix.gz

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PROLOG
       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of this interface
       may differ (consult the corresponding Linux manual page for details of Linux behavior), or the  interface
       may not be implemented on Linux.


NAME
       unsetenv — remove an environment variable


SYNOPSIS
       #include <stdlib.h>

       int unsetenv(const char *name);


DESCRIPTION
       The unsetenv() function shall remove an environment variable from the environment of the calling process.
       The name argument points to a string, which is the name of the variable to be removed. The named argument
       shall  not contain an '=' character. If the named variable does not exist in the current environment, the
       environment shall be unchanged and the function is considered to have completed successfully.

       The unsetenv() function shall update the list of pointers to which environ points.

       The unsetenv() function need not be thread-safe.


RETURN VALUE
       Upon successful completion, zero shall be returned.  Otherwise,  −1  shall  be  returned,  errno  set  to
       indicate the error, and the environment shall be unchanged.


ERRORS
       The unsetenv() function shall fail if:

       EINVAL The name argument points to an empty string, or points to a string containing an '=' character.

       The following sections are informative.


EXAMPLES
       None.


APPLICATION USAGE
       None.


RATIONALE
       Refer to the RATIONALE section in setenv().


FUTURE DIRECTIONS
       None.


SEE ALSO
       getenv(), setenv()

       The Base Definitions volume of POSIX.1‐2008, <stdlib.h>, <sys_types.h>


       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition,
       Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open  Group  Base
       Specifications  Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc
       and The Open Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In  the  event
       of  any  discrepancy between this version and the original IEEE and The Open Group Standard, the original
       IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at
       http://www.unix.org/online.html .

       Any  typographical  or formatting errors that appear in this page are most likely to have been introduced
       during  the  conversion  of  the  source  files  to  man  page  format.  To  report  such   errors,   see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .