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unsetenv(3p) — Linux manual page

UNSETENV(3P)            POSIX Programmer's ManualUNSETENV(3P)

PROLOG        top

       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        top

       unsetenv — remove an environment variable

SYNOPSIS        top

       #include <stdlib.h>       int unsetenv(const char *name);

DESCRIPTION        top

       Theunsetenv() function shall remove an environment variable from       the environment of the calling process. Thename 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.       Theunsetenv() function shall update the list of pointers to whichenviron points.       Theunsetenv() function need not be thread-safe.

RETURN VALUE        top

       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        top

       Theunsetenv() function shall fail if:EINVALThename argument points to an empty string, or points to a              string containing an'='character.The following sections are informative.

EXAMPLES        top

       None.

APPLICATION USAGE        top

       None.

RATIONALE        top

       Refer to the RATIONALE section insetenv(3p).

FUTURE DIRECTIONS        top

       None.

SEE ALSO        top

getenv(3p),setenv(3p)       The Base Definitions volume of POSIX.1‐2017,stdlib.h(0p),sys_types.h(0p)

COPYRIGHT        top

       Portions of this text are reprinted and reproduced in electronic       form from IEEE Std 1003.1-2017, Standard for Information       Technology -- Portable Operating System Interface (POSIX), The       Open Group Base Specifications Issue 7, 2018 Edition, Copyright       (C) 2018 by the Institute of Electrical and Electronics Engineers,       Inc and The Open Group.  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 athttp://www.opengroup.org/unix/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, seehttps://www.kernel.org/doc/man-pages/reporting_bugs.html .IEEE/The Open Group                2017UNSETENV(3P)

Pages that refer to this page:stdlib.h(0p), getenv(3p), setenv(3p)

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