tempnam - create a name for a temporary file
#include <stdio.h>
char *tempnam(const char *dir, const char *pfx);Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
Never use this function. Use mkstemp(3) or
tmpfile(3) instead.
The tempnam() function returns a pointer to a string
that is a valid filename, and such that a file with this name did not
exist when tempnam() checked. The filename suffix of
the pathname generated will start with pfx in case pfx
is a non-NULL string of at most five bytes. The directory prefix part of
the pathname generated is required to be "appropriate" (often that at
least implies writable).
Attempts to find an appropriate directory go through the following steps:
In case the environment variable TMPDIR exists and contains the name of an appropriate directory, that is used.
Otherwise, if the dir argument is non-NULL and appropriate,
it is used.
Otherwise, P_tmpdir (as defined in <stdio.h>)
is used when appropriate.
Finally an implementation-defined directory may be used.
The string returned by tempnam() is allocated using malloc(3) and hence should be freed by free(3).
On success, the tempnam() function returns a pointer
to a unique temporary filename. It returns NULL if a unique name cannot
be generated, with errno set to indicate the error.