TMPNAM(3P)

💖 tmpnam(3P) — the create-a-name-for-a-temporary-file situation 💖

okay so bestie, welcome to TMPNAM(3P) from the POSIX Programmer's Manual. Buckle up, because this one is short but it is messy. 🫶

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✨ PROLOG ✨

real talk first: this manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (so pls consult the corresponding Linux manual page for the tea on Linux behavior), or the interface may not even be implemented on Linux at all. 💀

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🌸 NAME 🌸

tmpnam — create a name for a temporary file

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🎀 SYNOPSIS 🎀

#include <stdio.h>

char *tmpnam(char *s);

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🦋 DESCRIPTION 🦋

Okay so 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 — no drama intended, fr fr. This volume of POSIX.1‐2017 defers to the ISO C standard.

The tmpnam() 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. 😭 it's giving "technically valid, practically chaotic".

The tmpnam() 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 — iykyk, that means nobody promised you anything.

The implementation shall behave as if no function defined in this volume of POSIX.1‐2017, except tempnam(), calls tmpnam().

⚠️ Also, tmpnam() need not be thread-safe if called with a NULL parameter. Not me warning you twice. 💅

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🌈 RETURN VALUE 🌈

Upon successful completion, tmpnam() shall return a pointer to a string. If no suitable string can be generated, the tmpnam() function shall return a null pointer.

If the argument s is a null pointer, tmpnam() shall leave its result in an internal static object and return a pointer to that object. Subsequent calls to tmpnam() may modify the same object — so that pointer you're holding? Yeah, it's not yours forever bestie. 🙈

If the argument s is not a null pointer, it is presumed to point to an array of at least L_tmpnam chars; tmpnam() shall write its result in that array and shall return the argument as its value. Slay, it just hands you back what you gave it. ✨

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💜 ERRORS 💜

No errors are defined. 🎀 Periodt.

The following sections are informative.

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🍓 EXAMPLES 🍓

Generating a Pathname 🧚

The following example generates a unique pathname and stores it in the array pointed to by ptr.

#include <stdio.h>
...
char pathname[L_tmpnam+1];
char *ptr;

ptr = tmpnam(pathname);

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💅 APPLICATION USAGE 💅

Okay bestie, listen. This function only creates pathnames. It is the application's responsibility to create and remove the files. Not the function's problem. 🫶

😭 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. Classic race condition main character energy.

Applications may find tmpfile() more useful.

Applications should use the tmpfile(), mkstemp(), or mkdtemp() functions instead of the obsolescent tmpnam() function. Yeah. It's giving deprecated. It's giving "we're not mad, we're just disappointed". 💀

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👑 RATIONALE 👑

None. Nothing. Nada. The committee said no thoughts, head empty. ✨

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🔥 FUTURE DIRECTIONS 🔥

The tmpnam() function may be removed in a future version. So like… don't get attached. 💔

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⭐ SEE ALSO ⭐

• fopen()
• open()
• mkdtemp()
• tempnam()
• tmpfile()
• unlink()

The Base Definitions volume of POSIX.1‐2017, <stdio.h>

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🌸 COPYRIGHT 🌸

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. 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.opengroup.org/unix/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 .

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and that's the whole page, bestie!! shoutout to IEEE/The Open Group, 2017 for the source and date — this was TMPNAM(3P) and you ate that. 💖✨🎀🦋🌸💅🫶