NAME

       umask — set file creation mode mask

LIBRARY

       Standard C Library (libc, -lc)

SYNOPSIS

       #include <sys/stat.h>

       mode_t
       umask(mode_t numask);

DESCRIPTION

       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), and mkfifo(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.

RETURN VALUES

       The previous value of the file mode mask is returned by the call.

ERRORS

       The umask() system call is always successful.

SEE ALSO

       chmod(2), mkfifo(2), mknod(2), open(2)

STANDARDS

       The umask() system call is expected to conform to ISO/IEC 9945-1:1990 (“POSIX.1”).

HISTORY

       The umask() function appeared in Version 7 AT&T UNIX.

Debian                                            June 4, 1993                                          UMASK(2)