/*

@deftypefn Supplemental char* tmpnam (char *@var{s})

This function attempts to create a name for a temporary file, which
will be a valid file name yet not exist when @code{tmpnam} checks for
it.  @var{s} must point to a buffer of at least @code{L_tmpnam} bytes,
or be @code{NULL}.  Use of this function creates a security risk, and it must
not be used in new projects.  Use @code{mkstemp} instead.

@end deftypefn

*/

#include <stdio.h>

#ifndef L_tmpnam
#define L_tmpnam 100
#endif
#ifndef P_tmpdir
#define P_tmpdir "/usr/tmp"
#endif

static char tmpnam_buffer[L_tmpnam];
static int tmpnam_counter;

extern int getpid (void);

char *
tmpnam (char *s)
{
 int pid = getpid ();

 if (s == NULL)
   s = tmpnam_buffer;

 /*  Generate the filename and make sure that there isn't one called
     it already.  */

 while (1)
   {
     FILE *f;
     sprintf (s, "%s/%s%x.%x", P_tmpdir, "t", pid, tmpnam_counter);
     f = fopen (s, "r");
     if (f == NULL)
       break;
     tmpnam_counter++;
     fclose (f);
   }

 return s;
}