[RFA] gdb/win32-nat.c: check for NULL before calling strtoul

[Michael Elizabeth Chastain <chastain@cygnus.com>]

This patch fixes PR gdb/43, a coding error in child_attach.  Cygwin's
implementation of strtoul dumps core if the input pointer is NULL.
This means gdb dumps core on a plain "attach" command with no arguments.

This fix enables the test script gdb.base/default.exp to run to
completion.

I tested this on Windows 2000 Professional + cygwin 1.1.8.  I gave a
plain "attach" command by hand and also ran gdb.base/default.exp.

OK to apply?

Michael

===

2001-03-17  Michael Chastain  <chastain@redhat.com>

	* win32-nat.c (child_attach): check args for NULL before passing
	to strtoul.  This fixes PR gdb/43.

Index: gdb/win32-nat.c
===================================================================
RCS file: /cvs/src/src/gdb/win32-nat.c,v
retrieving revision 1.25
diff -c -3 -p -r1.25 win32-nat.c
*** gdb/win32-nat.c	2001/03/06 08:21:18	1.25
--- gdb/win32-nat.c	2001/03/18 07:40:02
*************** static void
*** 1015,1025 ****
  child_attach (char *args, int from_tty)
  {
    BOOL ok;
!   DWORD pid = strtoul (args, 0, 0);
  
    if (!args)
      error_no_arg ("process-id to attach");
  
    ok = DebugActiveProcess (pid);
  
    if (!ok)
--- 1015,1026 ----
  child_attach (char *args, int from_tty)
  {
    BOOL ok;
!   DWORD pid;
  
    if (!args)
      error_no_arg ("process-id to attach");
  
+   pid = strtoul (args, 0, 0);
    ok = DebugActiveProcess (pid);
  
    if (!ok)