NAME

umask − set and get file creation mask

SYNOPSIS

int umask (cmask)
int cmask;

DESCRIPTION

Umask sets the process’s file mode creation mask to cmask and returns the previous value of the mask.  Only the low-order 9 bits of cmask and the file mode creation mask are used. 

The file mode creation mask is used whenever a file is created by creat(2), mknod(2) or open(2). The actual mode (see chmod(2)) of the newly-created file is the difference between the given mode and cmask. In other words, cmask shows the bits to be turned off when a new file is created. 

The previous value of cmask is returned by the call.  The value is initially 022, which is an octal ‘mask’ number representing the complement of the desired mode.  ‘022’ here means that no permissions are withheld from the owner, but write permission is forbidden to group and to others.  Its complement, the mode of the file, would be 755.  The file mode creation mask is inherited by child processes. 

RETURN VALUE

The previous value of the file mode creation mask is returned. 

SEE ALSO

mkdir(1), sh(1), chmod(2), creat(2), mknod(2), open(2). 

ASSEMBLER

moveq#60,D0
movlcmask,A0
trap#0

The previous value of umask is returned to D0. 

Version 3.6  —  December 20, 1987