Ryan Dietrich wrote:
Hi,
Greetings, I've been studying how to interface C++ and Perl using XS.
I was aware of this project, and saw that it is doing things that are
currently beyond my skillset.
I was hoping I could get a few answers.
1. What is the general approach of handling exceptions?
At the moment there is partial support for handling exceptions in
XS++: by default all exceptions are caught, and the XS wrapper die()s
with a message. If the exception is derived from std::exception, the
message includes the text of the what() method, otherwise a generic
error message is thrown. Support for propagating the complete exception
object to Perl is planned but not implemented yet.
If for any reason you don't want to use XS++, you need to put a
try/catch block around the XS code and handle the exceptions manually
int
foo(int bar)
CODE:
try [
RETVAL = foo(bar);
} catch (...) {
...
}
OUTPUT: RETVAL
2. How do you map multiple custom C++ objects out of a single header file
using XS?
There are two approaches:
1 - you can split the XS code in multiple XS files and then include them
all in a single top-level file, using the INCLUDE: directive; in this
case you do not need to do anything special
2 - if you do it the way Wx does, you need to list all the object files
for XS top-level modules in the OBJECTS MakeMaker parameter; every
top-level XS file must have a different MODULE directive; one of the XS
files must have a MODULE directive matching the .pm module name, and in
this module you need to add this code:
// in the C section
extern "C" {
XS( boot_SubModule1 );
XS( boot_Another_Sub_Module );
...
}
// in the XS section:
BOOT:
newXSproto( "My::_boot_SubModule1", boot_SubModule1, file, "$$" );
...
// in the My.pm file
_boot_SubModule1( 'My', $XS_VERSION );
Note that Wx uses a hybrid approach (multiple top-level XS files that
each include multiple XS files from the XS subdirectory).
For reference, here's my post on Perlmonks (it's a little wordy).
http://perlmonks.org/?node_id=853194
HTH,
Mattia
