I have changed cxx.cc a bit because it is only needed when the dll is
build via gcc3. gcc2 does not need libstdc++ at all because the
operators are contained in libgcc.
BTW, if someone is interested why better use sjlj instead of dwarf2
exceptions there is actually a thread on the mingw users mailing list
called "DLLs and Exceptions" discussing the pros and cons of sjlj and
dwarf2.
Whatever exception type is preferred by the cygwin gcc package i do not
think that the cygwin1.dll should ever throw an exception.
2002-11-26 Thomas Pfaff <[EMAIL PROTECTED]>
* cxx.cc: New file. Implement new, new[], delete and delete[]
operators and __cxa_pure_virtual if compiled by gcc >=3.
* Makefile.in (DLL_OFILES): Add cxx.o.
Remove libstdc++.a from cygwin1.dll link step.
On Tue, 26 Nov 2002, Thomas Pfaff wrote:
>
> I had some problems building the cygwin1.dll after i changed gcc to use
> sjlj exceptions. The resulting dll was unusable.
>
> I have discovered that this is due to the fact that cygwin1 is linked
> against libstdc++. The only reasons why cygwin1 is linked against stdc++
> are the operators new and delete and __cxa_pure_virtual.
>
> IMHO this is not acceptable because the new and new[] operators will throw
> exceptions if the memory allocation has failed. C programs will terminate
> via abort because the exception is not caught, C++ programs might behave
> unpredictable.
>
> A possible solution might be to use the nothrow new operators, i think
> that the cleanest way is to define own operators. As a side effect the
> cygwin1 dll can be build with an sjlj gcc and the dll is
> significantly smaller.
>
> Thomas
>
> 2002-11-26 Thomas Pfaff <[EMAIL PROTECTED]>
>
> * cxx.cc: New file. Implement new, new[], delete and delete[]
> operators. Implement __cxa_pure_virtual.
> * Makefile.in (DLL_OFILES): Add cxx.o.
> Remove libstdc++.a from cygwin1.dll link step.
>
>
>
diff -urpN src.old/winsup/cygwin/Makefile.in src/winsup/cygwin/Makefile.in
--- src.old/winsup/cygwin/Makefile.in 2002-10-21 03:03:32.000000000 +0200
+++ src/winsup/cygwin/Makefile.in 2002-11-26 11:09:38.000000000 +0100
@@ -124,7 +124,7 @@ MALLOC_OFILES=@MALLOC_OFILES@
DLL_IMPORTS:=$(w32api_lib)/libkernel32.a
# Please maintain this list in sorted order, with maximum files per 80 col line
-DLL_OFILES:=assert.o autoload.o cygheap.o cygserver_client.o \
+DLL_OFILES:=assert.o autoload.o cxx.o cygheap.o cygserver_client.o \
cygserver_transport.o cygserver_transport_pipes.o \
cygserver_transport_sockets.o cygthread.o dcrt0.o debug.o \
delqueue.o dir.o dlfcn.o dll_init.o dtable.o environ.o errno.o \
@@ -263,7 +263,7 @@ maintainer-clean realclean: clean
new-$(DLL_NAME): $(LDSCRIPT) $(DLL_OFILES) $(DEF_FILE) $(DLL_IMPORTS) $(LIBC) $(LIBM)
$(API_VER) Makefile winver_stamp
$(CXX) $(CXXFLAGS) -nostdlib -Wl,-T$(firstword $^) -Wl,--out-implib,cygdll.a
-shared -o $@ \
-e $(DLL_ENTRY) $(DEF_FILE) $(DLL_OFILES) version.o winver.o \
- $(MALLOC_OBJ) $(LIBM) -lstdc++ $(LIBC) \
+ $(MALLOC_OBJ) $(LIBM) $(LIBC) \
-lgcc $(DLL_IMPORTS)
# Rule to build libcygwin.a
diff -urpN src.old/winsup/cygwin/cxx.cc src/winsup/cygwin/cxx.cc
--- src.old/winsup/cygwin/cxx.cc 1970-01-01 01:00:00.000000000 +0100
+++ src/winsup/cygwin/cxx.cc 2002-11-28 17:03:40.000000000 +0100
@@ -0,0 +1,49 @@
+/* cxx.cc
+
+ Copyright 2002 Red Hat, Inc.
+
+This file is part of Cygwin.
+
+This software is a copyrighted work licensed under the terms of the
+Cygwin license. Please consult the file "CYGWIN_LICENSE" for
+details. */
+
+#if (__GNUC__ >= 3)
+
+#include "winsup.h"
+#include <stdlib.h>
+
+void *
+operator new (size_t s)
+{
+ void *p = malloc (s);
+ if (p)
+ memset (p,0,s);
+ return p;
+}
+
+void
+operator delete (void *p)
+{
+ free (p);
+}
+
+void *
+operator new[] (size_t s)
+{
+ return ::operator new (s);
+}
+
+void
+operator delete[] (void *p)
+{
+ ::operator delete (p);
+}
+
+extern "C" void
+__cxa_pure_virtual (void)
+{
+ api_fatal ("pure virtual method called");
+}
+
+#endif
