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Newsgroups: comp.os.msdos.djgpp
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From: kunst AT prl DOT philips DOT nl (Pieter Kunst)
Subject: Re: Patch for tmpnam() (v2)
Sender: news AT prl DOT philips DOT nl (USENET News System)
Organization: Philips Research Laboratories, Eindhoven, The Netherlands
References: <DDMwL1 DOT Iw5 AT jade DOT mv DOT net>
Date: Mon, 21 Aug 1995 14:14:01 GMT
Lines: 48
To: djgpp AT sun DOT soe DOT clarkson DOT edu
Dj-Gateway: from newsgroup comp.os.msdos.djgpp

In article <DDMwL1 DOT Iw5 AT jade DOT mv DOT net> Marc Singer <nbn.nbn.com!sapien!elf> writes:
>Ok.  It isn;t really a `patch'.  Here is a version of tmpname() that
>does not bomb if $TMP doesn't end with a path separator.
>
>-------------------- cut -------------------- 
>char *
>tmpnam(char *s)
>{
>  static char static_buf[L_tmpnam];
>  static char tmpcount[] = "dj000000";
>  static const char *tmp_dir=0;
>  static int tmp_len;
>  int i;
>  char* pchCount;
>
>  if (tmp_dir == 0)
>  {
>    tmp_dir = getenv("TMPDIR");
>    if (!tmp_dir || access(tmp_dir, D_OK))
>    {
>      tmp_dir = getenv("TEMP");
>      if (!tmp_dir || access(tmp_dir, D_OK))
>      {
>	tmp_dir = getenv("TMP");
>	if (!tmp_dir || access(tmp_dir, D_OK))
>	  tmp_dir = "c:/";
>      }
>    }
>    tmp_len = strlen(tmp_dir);
>  }
>
>  if (!s)
>    s = static_buf;
>  strcpy(s, tmp_dir);

[rest of code deleted...]


This code might not work properly with the following sequence:
 
    tmpnam();           /* tmp_dir points to getenv() static data buffer */
    getenv("SOMEVAR");  /* subsequent call to getenv() fills static data */
    tmpnam();           /* might fail due to static data overwrite */
                        /* i.e. tmp_dir points to SOMEVAR getenv() result */

Better make a local copy of the getenv() result.

Pieter.