NAME

umask − Sets and gets the value of the file creation mask

SYNOPSIS

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

STANDARDS

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. 

PARAMETERS

cmaskSpecifies the value of the file mode creation mask. 

DESCRIPTION

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. 

RETURN VALUES

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. 

ERRORS

No errors are defined. 

SEE ALSO

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)

Standards: standards(5)