How do I find the 'temp' directory in Linu

Question

How do I find the 'temp' directory in Linux? I am writing a platform neutral C++ function that returns the temp directory. In Mac and Windows, there is an API that returns these results. In Linux, I'm stumped. ­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­

Answer 1

Check following variables:

• The environment variable TMPDIR
• The value of the P_tmpdir macro

If all fails try to use the directory /tmp.

You can also use tempnam function to generate a unique temporary file name.

Answer 2

Edit: Fair point from the commenter. tmpnam isn't a good choice these days; use mktemp/mkstemp instead.

Historical answer: Be POSIX compliant, and use tmpnam (which will give you a full filename in a temporary location).

Answer 3

Use the value of the $TMPDIR environment variable, and if that doesn't exist, use /tmp.

Answer 4

In standard c, you could try: P_tmpdir

Answer 5

The accepted sequence, specifically from a GNU standpoint, is:

1. Check the environmental variable TMPDIR (getenv("TMPDIR")) only if the program is not running as SUID/SGID (issetugid() == 0)
2. Otherwise use P_tmpdir if it is defined and is valid
3. and finally, should those fail, use _PATH_TMP available from paths.h

If you are adding an extension or module, check to see if the core provides a function for this purpose. For example, PHP exports php_get_temporary_directory() from main/php_open_temporary_file.h.