TEMPNAM(3P)

💖 TEMPNAM(3P) — POSIX Programmer's Manual 💖

okay so bestie, we're in the POSIX Programmer's Manual, this is TEMPNAM(3P), and it's giving "let me name a temp file for you" energy. before we even start, real talk:

⚠️ PROLOG ⚠️ — this manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (so go consult the corresponding Linux manual page for the tea on Linux behavior), or honestly the interface may not be implemented on Linux at all. so like, check first, i'm begging 🫶

---

✨ NAME ✨

tempnam — create a name for a temporary file 🌸

---

🎀 SYNOPSIS 🎀

#include <stdio.h>

char *tempnam(const char *dir, const char *pfx);

---

💅 DESCRIPTION 💅

The tempnam() function shall generate a pathname that may be used for a temporary file. it's not making the file, it's just making the name, and that distinction is lowkey the whole plot of this page, so remember it.

The tempnam() function allows the user to control the choice of a directory. like, you get a say 💁‍♀️ The dir argument points to the name of the directory in which the file is to be created. If dir is a null pointer or points to a string which is not a name for an appropriate directory, the path prefix defined as P_tmpdir in the <stdio.h> header shall be used. And if that directory is not accessible, an implementation-defined directory may be used. so it's got backup plans, iconic.

Many applications prefer their temporary files to have certain initial letter sequences in their names — main character naming rights, basically. The pfx argument should be used for this. This argument may be a null pointer or point to a string of up to five bytes to be used as the beginning of the filename. five bytes, bestie. not six. not a whole novel. five. 🍓

Some implementations of tempnam() may use tmpnam() internally. On such implementations, if called more than {TMP_MAX} times in a single process, the behavior is implementation-defined. so yeah, that's a little ominous, no cap.

---

⭐ RETURN VALUE ⭐

Upon successful completion, tempnam() shall allocate space for a string, put the generated pathname in that space, and return a pointer to it. that pointer shall be suitable for use in a subsequent call to free(). like, you HAVE to free it, it's yours now, you're responsible for it 🙈

Otherwise, it shall return a null pointer and set errno to indicate the error. sad girl hours.

---

😭 ERRORS 😭

The tempnam() function shall fail if:

• ENOMEM — Insufficient storage space is available. bestie the memory said no 💀

The following sections are informative.

---

🌈 EXAMPLES 🌈

🌸 Generating a Pathname 🌸

The following example generates a pathname for a temporary file in directory /tmp, with the prefix file. After the pathname has been created, the call to free() deallocates the space used to store the pathname. look at that responsible little cleanup, we love to see it 🫶

#include <stdio.h>
#include <stdlib.h>
...
const char *directory = "/tmp";
const char *fileprefix = "file";
char *file;

file = tempnam(directory, fileprefix);
free(file);

---

👑 APPLICATION USAGE 👑

okay this part is important so like, pay attention bestie:

This function only creates pathnames. It is the application's responsibility to create and remove the files. periodt. 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. yes, really. that's a whole race condition situation going on and nobody's stopping it 🚩 Applications may find tmpfile() more useful.

Applications should use the tmpfile(), mkdtemp(), or mkstemp() functions instead of the obsolescent tempnam() function. so like... tempnam() is the old one. it's giving "still invited to the party but nobody's texting it back" 😭

---

🧚 RATIONALE 🧚

None. (yeah. nothing. empty. the silence is the content 💀)

---

🦋 FUTURE DIRECTIONS 🦋

The tempnam() function may be removed in a future version. so don't get attached, bestie 💔

---

💜 SEE ALSO 💜

• fopen()
• free()
• mkdtemp()
• open()
• tmpfile()
• tmpnam()
• unlink()

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

---

📜 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 .

---

and that's the whole page, bestie!! this little number came to you courtesy of IEEE/The Open Group, dated 2017 — so like, throw a 🎀 in the group chat for them, and remember: name the file, then actually make the file yourself, and free() that pointer. slay 💅✨