creat(2) UNIX System V creat(2)
NAME
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, modet mode);
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 SISGID 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 SISGID 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 system calls [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, OWRONLY | OCREAT | OTRUNC, mode)
creat fails if one or more of the following are true:
EACCES Search permission is denied on a component of the
path prefix.
EACCES The file does not exist and the directory in which
the file is to be created does not permit writing.
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EACCES 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)].
EFAULT path points outside the allocated address space of
the process.
EISDIR The named file is an existing directory.
EINTR A signal was caught during the creat system call.
ELOOP Too many symbolic links were encountered in
translating path.
EMFILE The process has too many open files [see
getrlimit(2)].
ENAMETOOLONG The length of the path argument exceeds {PATHMAX},
or the length of a path component exceeds {NAMEMAX}
while POSIXNOTRUNC is in effect.
ENOTDIR A component of the path prefix is not a directory.
ENOENT A component of the path prefix does not exist.
ENOENT The path name is null.
EROFS The named file resides or would reside on a read-only
file system.
ETXTBSY The file is a pure procedure (shared text) file that
is being executed.
ENFILE The system file table is full.
ENOLINK path points to a remote machine and the link to that
machine is no longer active.
EMULTIHOP Components of path require hopping to multiple remote
machines.
ENOSPC The file system is out of inodes.
SEE ALSO
chmod(2), close(2), dup(2), fcntl(2), getrlimit(2), lseek(2), open(2),
read(2), umask(2), write(2), stat(5).
DIAGNOSTICS
Upon successful completion a non-negative integer, namely the lowest
numbered unused file descriptor, is returned. Otherwise, a value of -1
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is returned, no files are created or modified, and errno is set to
indicate the error.
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