umask.2

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 2 代码 · 共 49 行

.\" SCCSID: @(#)umask.2	8.1	9/11/90
.TH umask 2
.SH Name
umask \- set file creation mask
.SH Syntax
.B #include <sys/types.h>
.br
.B #include <sys/stat.h>
.PP
.B oumask = umask(\fInumask\fP)
.br
.B mode_t oumask, \fInumask\fP;
.fi
.SH Description
.NXR "umask system call"
.NXR "file" "setting mode mask"
The
.PN umask
system call
sets the process's file mode creation mask to 
.PN numask
and returns the previous value of the mask.  The low-order
nine bits of 
.PN numask
are used whenever a file is created,
clearing corresponding bits in the file mode.
(For further information, see 
.MS chmod 2 .)
This clearing allows each user to restrict the default access
to his or her files.
.PP
The value is initially 022 (write access for owner only).
The mask is inherited by child processes.
.PP
The previous value of the file mode mask is returned by the call.
.SH Environment
.PP
POSIX
.br
When your program is compiled in POSIX mode,
the
.I numask
argument is of type mode_t and the
.PN umask
function
returns a value of type mode_t.
.SH See Also
chmod(2), mknod(2), open(2)