Re: verbose terminate() on by default

[Phil Edwards <phil at jaj dot com>]

On Mon, Dec 23, 2002 at 08:41:36PM +0100, Gabriel Dos Reis wrote:
> Daniel Jacobowitz <drow@mvista.com> writes:
> 
> | Step back... Phil, your most recent patch just changed eh_terminate.cc,
> | if I'm looking at the right message.  That's in libsupc++.  But
> | verbose_terminate is in libstdc++.  I see a problem there; libsupc++
> | should not have link dependency on libstdc++, that defeats the point,
> | doesn't it?
> 
> Good catch!
> 
> But src/cterminate.cc should have been put in libsupc++/ in the first
> place.   

I agree.  I wonder why nobody noticed this last year.


> It currenlty uses:
> 
>    * free() // to free the storage allocated by the demangler
>    * abort() // which is already used in libsupc++

I'm not worried about either of those.  The routine used to deallocate
memory will probably have to be generalized if we start using Carlo's
less-buggy demangler.


>    * fprintf() // which might be effcienly replaced by write() or puts().

Replacing it with fputs() still brings in the stdio library.  Although I
think that it would still be an improvement, since it doesn't do string
interpretation and wouldn't (in theory) pull in as much stuff as fprtinf(),
assuming a well-divisioned stdio library.

Replacing it with write() would be a bad step, I think.  Now we have
multiple system calls, instead of a single one done after formatting.
Unless we want to format the string into a buffer ourselves before calling
write() once... at which point we're back to using fprintf.

Here's what it looks like:


Index: src/vterminate.cc
===================================================================
RCS file: /home/pme/Repositories/GCC/gcc/libstdc++-v3/src/vterminate.cc,v
retrieving revision 1.7
diff -u -3 -r1.7 vterminate.cc
--- src/vterminate.cc	18 Dec 2002 16:31:35 -0000	1.7
+++ src/vterminate.cc	24 Dec 2002 00:14:23 -0000
@@ -36,6 +36,8 @@
 using namespace std;
 using namespace abi;
 
+#define errwrite(s)  write(2,s,strlen(s))
+
 namespace __gnu_cxx
 {
   /* A replacement for the standard terminate_handler which prints
@@ -57,8 +59,12 @@
 	  
 	  dem = __cxa_demangle(name, 0, 0, &status);
 
-	  fprintf(stderr, "terminate called after throwing a `%s'\n", 
-		  status == 0 ? dem : name);
+	  errwrite("terminate called after throwing a `");
+	  if (status == 0)
+	    errwrite(dem);
+	  else
+	    errwrite(name);
+	  errwrite("'\n");
 
 	  if (status == 0)
 	    free(dem);
@@ -69,12 +75,17 @@
 	try { __throw_exception_again; }
 #ifdef __EXCEPTIONS
 	catch (exception &exc)
-	  { fprintf(stderr, "  what(): %s\n", exc.what()); }
+	  {
+	    char const *w = exc.what();
+	    errwrite("  what(): ");
+	    errwrite(w);
+	    errwrite("\n");
+          }
 #endif
 	catch (...) { }
       }
     else
-      fprintf(stderr, "terminate called without an active exception\n");
+      errwrite("terminate called without an active exception\n");
     
     abort();
   }