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@(#)creat.2 6.1 (Berkeley) 05/09/85

C 4 creat - create a new file

 creat(name, mode)  char *name; 

"This interface is obsoleted 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.

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) facilitity. The value -1 is returned if an error occurs. Otherwise, the call returns a non-negative descriptor which only permits writing. Creat will fail and the file will not be created or truncated if one of the following occur:

15 [EPERM] The argument contains a byte with the high-order bit set.

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

15 [EACCES] A needed directory does not have search permission.

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

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

15 [EISDIR] The file is a directory.

15 [EMFILE] There are already too many files open.

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

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

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

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

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

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

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