umask(2) BSD System Calls Manual umask(2)

NAME

 umask -- set file creation mode mask

SYNOPSIS

 #include <sys/stat.h>
 mode_t
 umask(mode_t cmask);

DESCRIPTION

 The umask() routine sets the process's file mode creation mask to cmask
 and returns the previous value of the mask. The 9 low-order access per-
 mission bits of cmask 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.

RETURN VALUES

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

ERRORS

 The umask() function is always successful.

LEGACY SYNOPSIS

 #include <sys/types.h>
 #include <sys/stat.h>
 The include file <sys/types.h> is necessary.

SEE ALSO

 chmod(2) , mkdir(2) , mkfifo(2) , mknod(2) , open(2) , compat(5) 

STANDARDS

 The umask() function call is expected to conform to IEEE Std 1003.1-1988
 (``POSIX.1'').
4th Berkeley Distribution June 4, 1993 4th Berkeley Distribution