MSVCRT: _tempnam not following documentation

[Phil Lodwick]

When working on a problem with _tempnam(".", NULL) failing, I saw that
_tempnam 
was not following the documented rules.  In particular:

_tempnam will generate a unique file name for a directory chosen by the
following rules:

 - If the TMP environment variable is defined and set to a valid directory
name,
   unique file names will be generated for the directory specified by TMP.

 - If the TMP environment variable is not defined or if it is set to the name

   of a directory that does not exist, _tempnam will use the dir parameter as

   the path for which it will generate unique names. 

 - If the TMP environment variable is not defined or if it is set to the name

   of a directory that does not exist, and if dir is either NULL or set to
the 
   name of a directory that does not exist, _tempnam will use the current
working 
   directory to generate unique names. Currently, if both TMP and dir specify
names 
   of directories that do not exist, the _tempnam function call will fail. 

This patch should implement these rules.

James Hawkins pointed out in my previous patch that I should write
conformance tests
And submit those as well.  I have a question for this case that I will ask on
wine-devel.

Phil

----

ChangeLog:
_tempnam uses the TMP environment variable

Index: dlls/msvcrt/file.c
===================================================================
RCS file: /home/wine/wine/dlls/msvcrt/file.c,v
retrieving revision 1.91
diff -u -r1.91 file.c
--- dlls/msvcrt/file.c	7 Oct 2005 15:01:15 -0000	1.91
+++ dlls/msvcrt/file.c	8 Nov 2005 21:40:37 -0000
@@ -1887,9 +1887,34 @@
 char *_tempnam(const char *dir, const char *prefix)
 {
   char tmpbuf[MAX_PATH];
+  char tmpdir[MAX_PATH];
+  BOOL HaveEnvVar;
 
   TRACE("dir (%s) prefix (%s)\n",dir,prefix);
-  if (GetTempFileNameA(dir,prefix,0,tmpbuf))
+  HaveEnvVar = (GetEnvironmentVariableA("TMP", tmpdir, MAX_PATH) != 0);
+  if (!HaveEnvVar || _access(tmpdir, 0) != 0)
+  {
+    BOOL UseCurrentWorkingDir = FALSE;
+
+    if (dir)
+    {
+      lstrcpynA(tmpdir, dir, MAX_PATH);
+      if (_access(tmpdir, 0) != 0)
+      {
+        if (!HaveEnvVar)
+           return NULL;
+        UseCurrentWorkingDir = TRUE;
+      }
+    }
+    else
+       UseCurrentWorkingDir = TRUE;
+
+    if (UseCurrentWorkingDir)
+       if (GetCurrentDirectoryA(MAX_PATH, tmpdir) < 1)
+          return NULL;
+  }
+
+  if (GetTempFileNameA(tmpdir,prefix,0,tmpbuf))
   {
     TRACE("got name (%s)\n",tmpbuf);
     DeleteFileA(tmpbuf);