UMASK Section: Linux Programmer's Manual (2) Updated: 9 August 2025 Index   NAME umask - set file creation mask   SYNOPSIS #include <sys/types.h> #include <sys/stat.h> mode_t umask(mode_t mask);   DESCRIPTION umask sets the umask to mask & 0777. The umask is used by to set initial file permissions on a newly-created file. Specifically, permissions in the umask are turned off from the mode argument to (so, for example, the common umask default value of 022 results in new files being created with permissions 0666 & ~022 = 0644 = rw-r--r-- in the usual case where the mode is specified as 0666).   RETURN VALUE This system call always succeeds and the previous value of the mask is returned.   CONFORMING TO SVr4, SVID, POSIX, X/OPEN, BSD 4.3   SEE ALSO   Index NAME SYNOPSIS DESCRIPTION RETURN VALUE CONFORMING TO SEE ALSO This document was created by using the manual pages. Time: 11:56:07 GMT, March 24, 2025