umask(3p) — Linux manual page


UMASK(3P)                 POSIX Programmer's Manual                UMASK(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

       umask — set and get the file mode creation mask

SYNOPSIS         top

       #include <sys/stat.h>

       mode_t umask(mode_t cmask);

DESCRIPTION         top

       The umask() function shall set the file mode creation mask of the
       process to cmask and return the previous value of the mask. Only the
       file permission bits of cmask (see <sys/stat.h>) are used; the
       meaning of the other bits is implementation-defined.

       The file mode creation mask of the process is used to turn off
       permission bits in the mode argument supplied during calls to the
       following functions:

        *  open(), openat(), creat(), mkdir(), mkdirat(), mkfifo(), and

        *  mknod(), mknodat()

        *  mq_open()

        *  sem_open()

       Bit positions that are set in cmask are cleared in the mode of the
       created file.

RETURN VALUE         top

       The file permission bits in the value returned by umask() shall be
       the previous value of the file mode creation mask. The state of any
       other bits in that value is unspecified, except that a subsequent
       call to umask() with the returned value as cmask shall leave the
       state of the mask the same as its state before the first call,
       including any unspecified use of those bits.

ERRORS         top

       No errors are defined.

       The following sections are informative.

EXAMPLES         top




RATIONALE         top

       Unsigned argument and return types for umask() were proposed. The
       return type and the argument were both changed to mode_t.

       Historical implementations have made use of additional bits in cmask
       for their implementation-defined purposes. The addition of the text
       that the meaning of other bits of the field is implementation-defined
       permits these implementations to conform to this volume of



SEE ALSO         top

       creat(3p), exec(1p), mkdir(3p), mkfifo(3p), mknod(3p), mq_open(3p),
       open(3p), sem_open(3p)

       The Base Definitions volume of POSIX.1‐2008, sys_stat.h(0p),

COPYRIGHT         top

       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 .

       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 .

IEEE/The Open Group                 2013                           UMASK(3P)

Pages that refer to this page: sys_stat.h(0p)mkdir(1p)sh(1p)umask(1p)exec(3p)execl(3p)execle(3p)execlp(3p)execv(3p)execve(3p)execvp(3p)mkdir(3p)mkdirat(3p)mkfifo(3p)mkfifoat(3p)mknod(3p)mknodat(3p)open(3p)posix_typed_mem_open(3p)shm_open(3p)