Manual page for creat(2)
creat - create a new file or rewrite an existing one
SYNOPSIS
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
int creat(const char *path,
mode_t mode);
MT-LEVEL
Async-Signal-Safe
DESCRIPTION
creat()
creates a new ordinary file or prepares to rewrite an existing file
named by the
path name
pointed to by
path.
If the file exists, the length is truncated to 0 and the mode
and owner are unchanged.
If the file does not exist
the file's owner
ID
is set to the effective user
ID
of the process.
The group
ID
of the file
is set to the effective group
ID
of the process, or
if the S_ISGID bit is set in the parent directory then the group
ID
of the file is inherited from the parent directory.
The access permission bits of the file mode are set to the value of
mode
modified as follows:
-
- If the group
ID
of the new file does not match the effective group
ID
or one of the supplementary group
IDs, the S_ISGID bit is cleared.
- All bits set in the process's file mode creation mask are cleared
(see
umask.2
- The ``save text image after execution bit'' of the mode is cleared
(see
chmod.2
for the values of mode).
Upon successful completion,
a write-only file descriptor
is returned and the file is open for writing,
even if the mode does not permit writing.
The file pointer is set to the beginning of the file.
The file descriptor is set to remain open across
exec
functions
(see
fcntl.2
A new file may be created with a mode that forbids writing.
The call creat(path, mode) is equivalent to:
open(path, O_WRONLY | O_CREAT | O_TRUNC, mode)
RETURN VALUES
Upon successful completion a non-negative integer,
namely the lowest numbered unused file descriptor,
is returned.
Otherwise, a value of -1 is returned, no files are created or modified, and
errno
is set to indicate the error.
ERRORS
creat()
fails if one or more of the following are true:
- EACCES
-
Search permission is denied on a component of the
path prefix.
The file does not exist and the directory in which the file
is to be created does not permit writing.
The file exists and write permission is denied.
- EAGAIN
-
The file exists,
mandatory file/record locking is set,
and there are outstanding record locks on the file
(see
chmod.2
- EDQUOT
-
The directory where the new file entry is being placed
cannot be extended because the user's quota of disk blocks
on that file system has been exhausted.
The user's quota of inodes on the file system where
the file is being created has been exhausted.
- EFAULT
-
path
points to an illegal address.
- EINTR
-
A signal was caught during the
creat()
function.
- EISDIR
-
The named file is an existing directory.
- ELOOP
-
Too many symbolic links were encountered in translating path.
- EMFILE
-
The process has too many open files (see
getrlimit.2
- EMULTIHOP
-
Components of path require hopping to multiple remote machines.
- ENAMETOOLONG
-
The length of the path argument exceeds {PATH_MAX}, or the
length of a path component exceeds {NAME_MAX} while
{_POSIX_NO_TRUNC} is in effect.
- ENFILE
-
The system file table is full.
- ENOENT
-
A component of the path prefix does not exist.
The path name is null.
- ENOLINK
-
path points to a remote machine and the link
to that machine is no longer active.
- ENOSPC
-
The file system is out of inodes.
- ENOTDIR
-
A component of the path prefix is not a directory.
- EROFS
-
The named file resides or would reside on a read-only file system.
SEE ALSO
chmod.2
close.2
dup.2
fcntl.2
getrlimit.2
lseek.2
open.2
read.2
umask.2
write.2
stat.5
Created by unroff & hp-tools.
© by Hans-Peter Bischof. All Rights Reserved (1997).
Last modified 21/April/97
