mkstemp

#include <cstdlib>  // per IEEE Std 1003.1, 2004
#include <unistd.h> // for "legacy" systems
</sousyntaxhighlightrce>

===Declaration===
<code>int mkstemp(char* template);</code>

===Requirements===
* The parameter <code>template</code> must be a modifiable, null-terminated character array. 
* The contents of <code>template</code> must be in the format of a valid [[Path (computing)|file path]], with six trailing 'X's.
* The parameter <code>template</code> must not have been used in a previous invocation of <code>mkstemp</code>.

===Semantics===
* The trailing 'X's in <code>template</code> are overwritten to generate a unique [[Path (computing)|file name]] for the resulting temporary file.
* The function reports a valid [[file descriptor]] to a [[temporary file]] on success; on failure, it reports <code>-1</code>.

=== Example ===
The following code is an example of the usage of <code>mkstemp</code>; the local variable <code>filename</code> is modified by <code>mkstemp</code> and will contain the path to the new file:<ref name="Seacord2014"/>
<syntaxhighlight lang="c">
#include <stdlib.h>

void example()
{
    char filename[] = "/tmp/prefXXXXXX";
    mkstemp(filename);
}