'\" et

.TH TMPNAM "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

tmpnam

\(em create a name for a temporary file

.SH SYNOPSIS

.LP

.nf

#include <stdio.h>

.P

char *tmpnam(char *\fIs\fP);

.fi

.SH DESCRIPTION

The functionality described on this reference page is aligned with the

ISO\ C standard. Any conflict between the requirements described here and the

ISO\ C standard is unintentional. This volume of POSIX.1\(hy2008 defers to the ISO\ C standard.

.P

The

\fItmpnam\fR()

function shall generate a string that is a valid pathname that does not

name an existing file. The function is potentially capable of generating

{TMP_MAX}

different strings, but any or all of them may already be in use by

existing files and thus not be suitable return values.

.P

The

\fItmpnam\fR()

function generates a different string each time it is called from the

same process, up to

{TMP_MAX}

times. If it is called more than

{TMP_MAX}

times, the behavior is implementation-defined.

.P

The implementation shall behave as if no function defined in this volume of POSIX.1\(hy2008,

except

\fItempnam\fR(),

calls

\fItmpnam\fR().

.P

The

\fItmpnam\fR()

function need not be thread-safe if called with a NULL parameter.

.SH "RETURN VALUE"

Upon successful completion,

\fItmpnam\fR()

shall return a pointer to a string. If no suitable string can be

generated, the

\fItmpnam\fR()

function shall return a null pointer.

.P

If the argument

.IR s

is a null pointer,

\fItmpnam\fR()

shall leave its result in an internal static object and return a

pointer to that object. Subsequent calls to

\fItmpnam\fR()

may modify the same object. If the argument

.IR s

is not a null pointer, it is presumed to point to an array of at least

L_tmpnam

.BR char s;

\fItmpnam\fR()

shall write its result in that array and shall return the argument

as its value.

.SH ERRORS

No errors are defined.

.LP

.IR "The following sections are informative."

.SH EXAMPLES

.SS "Generating a Pathname"

.P

The following example generates a unique pathname and stores it in the

array pointed to by

.IR ptr .

.sp

.RS 4

.nf

\fB

#include <stdio.h>

\&...

char pathname[L_tmpnam+1];

char *ptr;

.P

ptr = tmpnam(pathname);

.fi \fR

.P

.RE

.SH "APPLICATION USAGE"

This function only creates pathnames. It is the application's

responsibility to create and remove the files.

.P

Between the time a pathname is created and the file is opened, it is

possible for some other process to create a file with the same name.

Applications may find

\fItmpfile\fR()

more useful.

.P

Applications should use the

\fItmpfile\fR(),

\fImkstemp\fR(),

or

\fImkdtemp\fR()

functions instead of the obsolescent

\fItmpnam\fR()

function.

.SH RATIONALE

None.

.SH "FUTURE DIRECTIONS"

The

\fItmpnam\fR()

function may be removed in a future version.

.SH "SEE ALSO"

.IR "\fIfopen\fR\^(\|)",

.IR "\fIopen\fR\^(\|)",

.IR "\fImkdtemp\fR\^(\|)",

.IR "\fItempnam\fR\^(\|)",

.IR "\fItmpfile\fR\^(\|)",

.IR "\fIunlink\fR\^(\|)"

.P

The Base Definitions volume of POSIX.1\(hy2008,

.IR "\fB<stdio.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 .

Any typographical or formatting errors that appear

in this page are most likely

to have been introduced during the conversion of the source files to

man page format. To report such errors, see

https://www.kernel.org/doc/man-pages/reporting_bugs.html .