Re: libtool, llvm-gcc, failing C++ exceptions

[Ralf Wildenhues]

Hi Bob,

* Bob Friesenhahn wrote on Mon, Jan 11, 2010 at 05:32:15AM CET:
> On Sun, 10 Jan 2010, Ralf Wildenhues wrote:
> >>
> >>My main comment is that it would be useful if the thrown class is
> >>derived from std:exception (or one of its standard derived classes)
> >>in order to flush out any issues which may stem from possible
> >>partial template instantiation in libstdc++ (or pre-compiled
> >>headers) as well as in the test translation unit.
> >
> >OK, sounds useful.  Would that entail more than just something like
> >this incremental addition?
> 
> I think that the virtual what() method needs to be provided or else
> you have only a partially implemented class:
[...]

Yup, indeed.  And we need to provide a throw()-qualified destructor as
well.

> But this is a better class to test with since it uses more standard
> library stuff and is therefore more likely to fail if something is
> wrong:
[...]

Thanks.  I'm pushing the test with this incremental addition squashed
into the first iteration of the patch, and listing you as second author.

Cheers,
Ralf

diff --git a/tests/exceptions.at b/tests/exceptions.at
index d551cb8..920b30e 100644
--- a/tests/exceptions.at
+++ b/tests/exceptions.at
@@ -29,7 +29,19 @@ AT_KEYWORDS([libltdl])
 CPPFLAGS="$LTDLINCL $CPPFLAGS"
 
 AT_DATA([module.h],
-[[class modexc { };
+[[#include <exception>
+#include <string>
+class modexc : public std::exception {
+public:
+  modexc (std::string str) : message (str) { }
+  ~modexc () throw () { }
+  virtual const char *what () const throw ()
+  {
+    return message.c_str ();
+  }
+private:
+  std::string message;
+};
 extern "C" int modfoo () throw (modexc);
 ]])
 
@@ -39,7 +51,7 @@ AT_DATA([module.cpp],
 
 int modbar (void) throw (modexc)
 {
-  throw modexc ();
+  throw modexc ("exception in module");
 }
 
 extern "C"
@@ -48,16 +60,28 @@ int modfoo (void) throw (modexc)
   try {
     modbar ();
   }
-  catch (modexc) {
-    std::cerr << "caught inside module\n";
-    throw modexc ();
+  catch (modexc e) {
+    std::cerr << "caught inside module: " << e.what () << '\n';
+    throw modexc ("exception from module");
   }
   return 0;
 }
 ]])
 
 AT_DATA([lib.h],
-[[class libexc { };
+[[#include <exception>
+#include <string>
+class libexc : public std::exception {
+public:
+  libexc (std::string str) : message (str) { }
+  ~libexc () throw () { }
+  virtual const char *what () const throw ()
+  {
+    return message.c_str ();
+  }
+private:
+  std::string message;
+};
 int libfoo () throw (libexc);
 ]])
 
@@ -67,7 +91,7 @@ AT_DATA([lib.cpp],
 
 int libbar (void) throw (libexc)
 {
-  throw libexc ();
+  throw libexc ("exception in library");
 }
 
 int libfoo (void) throw (libexc)
@@ -75,9 +99,9 @@ int libfoo (void) throw (libexc)
   try {
     libbar ();
   }
-  catch (libexc) {
-    std::cerr << "caught inside lib\n";
-    throw libexc ();
+  catch (libexc e) {
+    std::cerr << "caught inside lib: " << e.what () << '\n';
+    throw libexc ("exception from library");
   }
   return 0;
 }
@@ -87,14 +111,26 @@ AT_DATA([main.cpp],
 [[#include <ltdl.h>
 #include <cstdlib>
 #include <iostream>
+#include <exception>
+#include <string>
 #include "lib.h"
 #include "module.h"
 
-class exc { };
+class exc : public std::exception {
+public:
+  exc (std::string str) : message (str) { }
+  ~exc () throw () { }
+  virtual const char *what () const throw ()
+  {
+    return message.c_str ();
+  }
+private:
+  std::string message;
+};
 
 int foo (void) throw (exc)
 {
-  throw exc ();
+  throw exc ("exception in program");
   return 0;
 }
 
@@ -104,8 +140,8 @@ int exceptions_in_prog (void)
   try {
     foo ();
   }
-  catch (exc) {
-     std::cerr << "caught\n";
+  catch (exc e) {
+     std::cerr << "caught: " << e.what () << '\n';
     return 0;
   }
   return 1;
@@ -117,8 +153,8 @@ int exceptions_in_lib (void)
   try {
     libfoo ();
   }
-  catch (libexc) {
-     std::cerr << "caught\n";
+  catch (libexc e) {
+     std::cerr << "caught: " << e.what () << '\n';
     return 0;
   }
   return 1;
@@ -161,7 +197,8 @@ int exceptions_in_module (void)
   try {
     (*pf) ();
   }
-  catch (modexc) {
+  catch (modexc e) {
+    std::cerr << "caught: " << e.what () << '\n';
     if (lt_dlclose (handle))
       {
         std::cerr << "dlclose failed: " << lt_dlerror () << '\n';