umask(2POSIX)

NAME | SYNOPSIS | API RESTRICTIONS | FEATURES | DESCRIPTION | PARAMETERS | RETURN VALUES | ERRORS | ATTRIBUTES | SEE ALSO

NAME

umask- set file creation mode mask

SYNOPSIS

#include <sys/stat.h>

mode_t umask(mode_t numask);

API RESTRICTIONS

The function or functions documented here may not be used safely in all application contexts with all APIs provided in the ChorusOS 5.0 product.

See API(5FEA) for details.

FEATURES

NFS_CLIENT, UFS

DESCRIPTION

umask() sets the file mode creation mask for a process to numask and returns the previous value of the mask. The nine low-order access permission bits of numask are used by system calls, including mkdir(2POSIX), mkfifo(2POSIX) and open(2POSIX), to turn off corresponding bits requested in file mode. See chmod(2POSIX). This clearing allows users to restrict the default access to their own files.

The default mask value is S_IWGRP|S_IWOTH, or 022, providing write access for the owner only. Child processes inherit the mask of the calling process.

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Note -

Protection through umask is not supported with MSDOS file systems.

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PARAMETERS

umask() takes the parameter numask, which defines access permission bits.

RETURN VALUES

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

ERRORS

The umask() function is always successful.

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
Interface Stability	Evolving
MT-Level	Async-Signal-Safe

SEE ALSO

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

ChorusOS 5.0  Last Revised December 2001

NAME | SYNOPSIS | API RESTRICTIONS | FEATURES | DESCRIPTION | PARAMETERS | RETURN VALUES | ERRORS | ATTRIBUTES | SEE ALSO