+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in the
+.\" documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\" must display the following acknowledgement:
+.\" This product includes software developed by the University of
+.\" California, Berkeley and its contributors.
+.\" 4. Neither the name of the University nor the names of its contributors
+.\" may be used to endorse or promote products derived from this software
+.\" without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\" @(#)mktemp.3 6.10 (Berkeley) 4/19/91
+.\"
+.Dd April 19, 1991
+.Dt MKTEMP 3
+.Os
+.Sh NAME
+.Nm mktemp
+.Nd make temporary file name (unique)
+.Sh SYNOPSIS
+.Fd #include <unistd.h>
+.Ft char *
+.Fn mktemp "char *template"
+.Ft int
+.Fn mkstemp "char *template"
+.Sh DESCRIPTION
+The
+.Fn mktemp
+function
+takes the given file name template and overwrites a portion of it
+to create a file name.
+This file name is unique and suitable for use
+by the application.
+The template may be any file name with some number of
+.Ql X Ns s
+appended
+to it, for example
+.Pa /tmp/temp.XXXX .
+The trailing
+.Ql X Ns s
+are replaced with the current process number and/or a
+unique letter combination.
+The number of unique file names
+.Fn mktemp
+can return depends on the number of
+.Ql X Ns s
+provided; six
+.Ql X Ns s
+will
+result in
+.Fn mktemp
+testing roughly 26 ** 6 combinations.
+.Pp
+The
+.Fn mkstemp
+function
+makes the same replacement to the template and creates the template file,
+mode 0600, returning a file descriptor opened for reading and writing.
+This avoids the race between testing for a file's existence and opening it
+for use.
+.Sh RETURN VALUES
+The
+.Fn mktemp
+function
+returns a pointer to the template on success and
+.Dv NULL
+on failure.
+The
+.Fn mkstemp
+function
+returns \-1 if no suitable file could be created.
+If either call fails an error code is placed in the global variable
+.Va errno .
+.Sh ERRORS
+The
+.Fn mktemp
+and
+.Fn mkstemp
+functions
+may set
+.Va errno
+to one of the following values:
+.Bl -tag -width [ENOTDIR]
+.It Bq Er ENOTDIR
+The pathname portion of the template is not an existing directory.
+.El
+.Pp
+The
+.Fn mktemp
+and
+.Fn mkstemp
+functions
+may also set
+.Va errno
+to any value specified by the
+.Xr stat 2
+function.
+.Pp
+The
+.Fn mkstemp
+function
+may also set
+.Va errno
+to any value specified by the
+.Xr open 2
+function.
+.Sh SEE ALSO
+.Xr chmod 2 ,
+.Xr getpid 2 ,
+.Xr open 2 ,
+.Xr stat 2
+.Sh HISTORY
+A
+.Nm mktemp
+function appeared in
+.At v7 .
projects / unix-history / blobdiff