NAME

creat  −  create a new file

SYNOPSIS

creat(name, mode)
char *name;

DESCRIPTION

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 is used by programs which deal with temporary files of fixed names.  The creation is done with a mode that forbids writing.  Then if a second instance of the program attempts a creat, an error is returned and the program knows that the name is unusable for the moment. 

RETURN VALUE

Zero is returned if the file is created; −1 is returned otherwise. 

DIAGNOSTICS

Creat will fail and the file will not be created if:

[EACCES] A component of the path prefix denies search permission. 

[EACCES] The directory in which the file is to be created is not writable by the user. 

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

[EISDIR] The named file is a directory. 

[EMFILE] The maximum number of file descriptors allowed are already open. 

[ENFILE] No more system file descriptors are available, or there is insufficient system space to contain the i-node. 

[ENOENT] Element within path name does not exist. 

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

[ENXIO] Device special file within name is not for the current system (major device number is greater than "nchrdev"). 

[EROFS] The directory in which the file is to be created is on a read-only file system. 

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

SEE ALSO

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

ASSEMBLER

(creat = 8.) 
sys creat; name; mode
(file descriptor in r0)