'\" et
.TH MKDTEMP "3P" 2013 "IEEE/The Open Group" "POSIX Programmer's Manual"
.SH PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.

.SH NAME
mkdtemp, mkstemp
\(em create a unique directory or file
.SH SYNOPSIS
.LP
.nf
#include <stdlib.h>
.P
char *mkdtemp(char *\fItemplate\fP);
int mkstemp(char *\fItemplate\fP);
.fi
.SH DESCRIPTION
The
\fImkdtemp\fR()
function uses the contents of
.IR template
to construct a unique directory name. The string provided in
.IR template
shall be a pathname ending with six trailing
.BR 'X' s.
The
\fImkdtemp\fR()
function shall replace each
.BR 'X' 
with a character from the portable filename character set. The
characters are chosen such that the resulting name does not duplicate
the name of an existing file at the time of a call to
\fImkdtemp\fR().
The unique directory name is used to attempt to create the directory
using mode 0700 as modified by the file creation mask.
.P
The
\fImkstemp\fR()
function shall replace the contents of the string pointed to by
.IR template
by a unique pathname, and return a file descriptor for the file open
for reading and writing. The
\fImkstemp\fR()
function shall create the file, and obtain a file descriptor for it,
as if by a call to:
.sp
.RS 4
.nf
\fB
open(pathname, O_RDWR|O_CREAT|O_EXCL, S_IRUSR|S_IWUSR)
.fi \fR
.P
.RE
.P
The function thus prevents any possible race condition between testing
whether the file exists and opening it for use. The string in
.IR template
should look like a pathname with six trailing
.BR 'X' s;
\fImkstemp\fR()
replaces each
.BR 'X' 
with a character from the portable filename character set. The
characters are chosen such that the resulting name does not duplicate
the name of an existing file at the time of a call to
\fImkstemp\fR().
.SH "RETURN VALUE"
Upon successful completion, the
\fImkdtemp\fR()
function shall return a pointer to the string containing the directory
name if it was created. Otherwise, it shall return a null pointer and
shall set
.IR errno
to indicate the error.
.P
Upon successful completion, the
\fImkstemp\fR()
function shall return an open file descriptor. Otherwise, it shall
return \(mi1 if no suitable file could be created.
.SH ERRORS
The
\fImkdtemp\fR()
function shall fail if:
.TP
.BR EACCES
Search permission is denied on a component of the path prefix, or write
permission is denied on the parent directory of the directory to be
created.
.TP
.BR EINVAL
The string pointed to by
.IR template
does not end in
.BR \(dqXXXXXX\(dq .
.TP
.BR ELOOP
A loop exists in symbolic links encountered during resolution of the
path of the directory to be created.
.TP
.BR EMLINK
The link count of the parent directory would exceed
{LINK_MAX}.
.TP
.BR ENAMETOOLONG
.br
The length of a component of a pathname is longer than
{NAME_MAX}.
.TP
.BR ENOENT
A component of the path prefix specified by the
.IR template
argument does not name an existing directory.
.TP
.BR ENOSPC
The file system does not contain enough space to hold the contents of
the new directory or to extend the parent directory of the new
directory.
.TP
.BR ENOTDIR
A component of the path prefix names an existing file that is neither
a directory nor a symbolic link to a directory.
.TP
.BR EROFS
The parent directory resides on a read-only file system.
.P
The
\fImkdtemp\fR()
function may fail if:
.TP
.BR ELOOP
More than
{SYMLOOP_MAX}
symbolic links were encountered during resolution of the path of the
directory to be created.
.TP
.BR ENAMETOOLONG
.br
The length of a pathname exceeds
{PATH_MAX},
or pathname resolution of a symbolic link produced an intermediate
result with a length that exceeds
{PATH_MAX}.
.P
The error conditions for the
\fImkstemp\fR()
function are defined in
.IR "\fIopen\fR\^(\|)".
.LP
.IR "The following sections are informative."
.SH EXAMPLES
.SS "Generating a Pathname"
.P
The following example creates a file with a 10-character name beginning
with the characters
.BR \(dqfile\(dq 
and opens the file for reading and writing. The value returned as the
value of
.IR fd
is a file descriptor that identifies the file.
.sp
.RS 4
.nf
\fB
#include <stdlib.h>
\&...
char template[] = "/tmp/fileXXXXXX";
int fd;
.P
fd = mkstemp(template);
.fi \fR
.P
.RE
.SH "APPLICATION USAGE"
It is possible to run out of letters.
.P
The
\fImkdtemp\fR()
and
\fImkstemp\fR()
functions need not check to determine whether the filename part of
.IR template
exceeds the maximum allowable filename length.
.SH RATIONALE
None.
.SH "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.IR "\fIgetpid\fR\^(\|)",
.IR "\fImkdir\fR\^(\|)",
.IR "\fIopen\fR\^(\|)",
.IR "\fItmpfile\fR\^(\|)",
.IR "\fItmpnam\fR\^(\|)"
.P
The Base Definitions volume of POSIX.1\(hy2008,
.IR "\fB<stdlib.h>\fP"
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
(This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.unix.org/online.html .

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