[geos-devel] Exception Issues

[David Blasby]

I'm not 100% sure of the exact nature of the problem, but 
http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=37933
has some more technical details.

To summarize the article, the problem is not with the C++ exception 
mechanism; it works just fine if you link your program to libc++.  The 
problem is when you link the main program to libc (which doesnt 
understand c++ exception handling).  When the c++ code throws and 
exception that has to unwind the stack (ie. leave the function that 
threw it) a problem occurs because the default unwind mechinism in
libc is SIGABRT (terminate the program).

If the same program were linked to libc++, then the default unwind 
mechanism would handle the exception properly.

Anyways, read the article and see if my summary is accurate.

This isnt an issue in most program - a C program that is using libgeos 
would link it in at compile time.  This will cause it to link to libc++ 
not libc.

In postgresql, it is compiled and linked to libc.  When it want to load 
in postgis, it just openes up the .so at runtime (not compile time).

dave