NAME
creat - create a new file

SYNOPSIS
creat(name, mode)
const char *name;
int mode;

DESCRIPTION
This interface is made obsolete by open(2).

Creat creates a new file or prepares to rewrite an existing file
called name, given as the address of a null-terminated string. If
the file did not exist, it is given mode mode, as modified by the
process’s mode mask (see umask(2)). Also see chmod(2) for the
construction of the mode argument.

If the file did exist, its mode and owner remain unchanged but it
is truncated to 0 length.

The file is also opened for writing, and its file descriptor is
returned.

NOTES
The mode given is arbitrary; it need not allow writing. This
feature has been used in the past by programs to construct a
simple, exclusive locking mechanism. It is replaced by the O_EXCL
open mode, or flock(2) facility.

RETURN VALUE
The value -1 is returned if an error occurs. Otherwise, the call
returns a non-negative descriptor that only permits writing.

ERRORS
Creat will fail and the file will not be created or truncated if
one of the following occur:

[ENOTDIR] A component of the path prefix is not a directory.

[EINVAL] The pathname contains a character with the high-
order bit set.

[ENAMETOOLONG] A component of a pathname exceeded 255 characters,
or an entire path name exceeded 1023 characters.

[ENOENT] The named file does not exist.

[ELOOP] Too many symbolic links were encountered in
translating the pathname.

[EACCES] Search permission is denied for a component of the
path prefix.

[EACCES] The file does not exist and the directory in which
it is to be created is not writable.

[EACCES] The file exists, but it is unwritable.

[EISDIR] The file is a directory.

[EMFILE] There are already too many files open.

[ENFILE] The system file table is full.

[ENOSPC] The directory in which the entry for the new file is
being placed cannot be extended because there is no
space left on the file system containing the
directory.

[ENOSPC] There are no free inodes on the file system on which
the file is being created.

[EDQUOT] The directory in which the entry for the new file is
being placed cannot be extended because the user’s
quota of disk blocks on the file system containing
the directory has been exhausted.

[EDQUOT] The user’s quota of inodes on the file system on
which the file is being created has been exhausted.

[EROFS] The named file resides on a read-only file system.

[ENXIO] The file is a character special or block special
file, and the associated device does not exist.

[ETXTBSY] The file is a pure procedure (shared text) file that
is being executed.

[EIO] An I/O error occurred while making the directory
entry or allocating the inode.

[EFAULT] Name points outside the process’s allocated address
space.

[EOPNOTSUPP] The file was a socket (not currently implemented).

SEE ALSO
open(2), write(2), close(2), chmod(2), umask(2)