umask - Sets and gets the value of the file creation mask
#include <sys/types.h> #include <sys/stat.h>
mode_t cmask );
Interfaces documented on this reference page conform to
industry standards as follows:
umask(): POSIX.1, XSH4.0, XSH4.2, XSH5.0
Refer to the standards(5) reference page for more information
about industry standards and associated tags.
Specifies the value of the file mode creation mask.
The umask() function sets the file mode creation mask of
the process to the value of the cmask parameter and
returns the previous value of the mask. The cmask parameter
is constructed by a logical OR operation on the file
permission bits defined in the <sys/mode.h> header file.
Whenever a file is created (by the open(), mkdir(),
mkfifo(), or mknod() function), all file permission bits
set in the file mode creation mask are cleared in the mode
of the created file. This clearing lets users restrict the
default access to their files.
The mask is inherited by child processes.
Upon successful completion, the previous value of the file
mode creation mask is returned. The state of any other
bits in that value is unspecified, except that a subsequent
call to umask() with the returned value as cmask
will leave the mask in the same as its state before the
first call, including any unspecified use of those bits.
No errors are defined.
Commands: chmod(1), mkdir(1), Bourne shell sh(1b), POSIX
shell sh(1p), umask(1)
Functions: chmod(2), mkdir(2), mknod(2), open(2), stat(2)
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