[unix-history] / usr / man / man2 / creat.2

.TH CREAT 2 "2 July 1983"
.UC 4
.SH NAME
creat \- create a new file
.SH SYNOPSIS
.nf
.B creat(name, mode)
.B char *name;
.fi
.SH DESCRIPTION
.B "This interface is obsoleted by open(2).
.PP
.I Creat
creates a new file or prepares to rewrite an existing
file called 
.IR name ,
given as the address of a null-terminated string.
If the file did not exist, it is given
mode
.IR mode ,
as modified by the process's mode mask (see
.IR umask (2)).
Also see
.IR  chmod (2)
for the
construction of the
.I mode
argument.
.PP
If the file did exist, its mode and owner remain unchanged
but it is truncated to 0 length.
.PP
The file is also opened for writing, and its file descriptor
is returned.
.SH NOTES
The
.I 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 
.IR flock (2)
facilitity.
.SH "RETURN VALUE
The value \-1 is returned if an error occurs.  Otherwise,
the call returns a non-negative descriptor which only permits
writing.
.SH ERRORS
.I Creat
will fail and the file will not be created or truncated
if one of the following occur:
.TP 15
[EPERM]
The argument contains a byte with the high-order bit set.
.TP 15
[ENOTDIR]
A component of the path prefix is not a directory.
.TP 15
[EACCES]
A needed directory does not have search permission.
.TP 15
[EACCES]
The file does not exist and the directory
in which it is to be created is not writable.
.TP 15
[EACCES]
The file exists, but it is unwritable.
.TP 15
[EISDIR]
The file is a directory.
.TP 15
[EMFILE]
There are already too many files open.
.TP 15
[EROFS]
The named file resides on a read-only file system.
.TP 15
[ENXIO]
The file is a character special or block special file, and
the associated device does not exist.
.TP 15
[ETXTBSY]
The file is a pure procedure (shared text) file that is being
executed.
.TP 15
[EFAULT]
.I Name
points outside the process's allocated address space.
.TP 15
[ELOOP]
Too many symbolic links were encountered in translating the
pathname.
.TP 15
[EOPNOTSUPP]
The file was a socket (not currently implemented).
.SH "SEE ALSO"
open(2), write(2), close(2), chmod(2), umask(2)
Commit	Line	Data
df930a0c C	1	.TH CREAT 2 "2 July 1983"
	2	.UC 4
	3	.SH NAME
	4	creat \- create a new file
	5	.SH SYNOPSIS
	6	.nf
	7	.B creat(name, mode)
	8	.B char *name;
	9	.fi
	10	.SH DESCRIPTION
	11	.B "This interface is obsoleted by open(2).
	12	.PP
	13	.I Creat
	14	creates a new file or prepares to rewrite an existing
	15	file called
	16	.IR name ,
	17	given as the address of a null-terminated string.
	18	If the file did not exist, it is given
	19	mode
	20	.IR mode ,
	21	as modified by the process's mode mask (see
	22	.IR umask (2)).
	23	Also see
	24	.IR chmod (2)
	25	for the
	26	construction of the
	27	.I mode
	28	argument.
	29	.PP
	30	If the file did exist, its mode and owner remain unchanged
	31	but it is truncated to 0 length.
	32	.PP
	33	The file is also opened for writing, and its file descriptor
	34	is returned.
	35	.SH NOTES
	36	The
	37	.I mode
	38	given is arbitrary; it need not allow
	39	writing.
	40	This feature has been used in the past by
	41	programs to construct a simple exclusive locking
	42	mechanism. It is replaced by the O_EXCL open
	43	mode, or
	44	.IR flock (2)
	45	facilitity.
	46	.SH "RETURN VALUE
	47	The value \-1 is returned if an error occurs. Otherwise,
	48	the call returns a non-negative descriptor which only permits
	49	writing.
	50	.SH ERRORS
	51	.I Creat
	52	will fail and the file will not be created or truncated
	53	if one of the following occur:
	54	.TP 15
	55	[EPERM]
	56	The argument contains a byte with the high-order bit set.
	57	.TP 15
	58	[ENOTDIR]
	59	A component of the path prefix is not a directory.
	60	.TP 15
	61	[EACCES]
	62	A needed directory does not have search permission.
	63	.TP 15
	64	[EACCES]
65	The file does not exist and the directory
66	in which it is to be created is not writable.
67	.TP 15
68	[EACCES]
69	The file exists, but it is unwritable.
70	.TP 15
71	[EISDIR]
72	The file is a directory.
73	.TP 15
74	[EMFILE]
75	There are already too many files open.
76	.TP 15
77	[EROFS]
78	The named file resides on a read-only file system.
79	.TP 15
80	[ENXIO]
81	The file is a character special or block special file, and
82	the associated device does not exist.
83	.TP 15
84	[ETXTBSY]
85	The file is a pure procedure (shared text) file that is being
86	executed.
87	.TP 15
88	[EFAULT]
89	.I Name
90	points outside the process's allocated address space.
91	.TP 15
92	[ELOOP]
93	Too many symbolic links were encountered in translating the
94	pathname.
95	.TP 15
96	[EOPNOTSUPP]
97	The file was a socket (not currently implemented).
98	.SH "SEE ALSO"
99	open(2), write(2), close(2), chmod(2), umask(2)