umask - set file creation mode mask
Standard C Library (libc, -lc)
The umask() routine sets the process's file mode creation mask to numask
and returns the previous value of the mask. The 9 low-order access permission
bits of numask are used by system calls, including open(2),
mkdir(2), mkfifo(2) and mknod(2) to turn off corresponding bits requested
in file mode. (See chmod(2)). This clearing allows each user to
restrict the default access to his files.
The default mask value is S_IWGRP|S_IWOTH (022, write access for the
owner only). Child processes inherit the mask of the calling process.
The previous value of the file mode mask is returned by the call.
The umask() function is always successful.
chmod(2), mkdir(2), mkfifo(2), mknod(2), open(2)
The umask() function conforms to ISO/IEC 9945-1:1990 (``POSIX.1'').
BSD June 4, 1993 BSD
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