coppro
Level: Smitemaster
Rank Points: 1309
Registered: 11-24-2005
IP: Logged

The expat callbacks used by CDbXML are static class members, but since expat is a C interface, it is nonportable to use anything but an extern "C" global function for the callbacks. I would recommend inserting just before each callback function something like:

extern "C" DbXMLCTallyElementCForward (void * ud, const char * name, const char ** atts) { CDbXml::TallyElement(ud, name, atts); }

void CDbXml::TallyElement(
...

schep
Level: Smitemaster

Rank Points: 865
Registered: 03-01-2005
IP: Logged

This is technically true, but I'm curious: was there somewhere this actually came up? I've never seen a compiler that treated function pointers with and without 'extern "C"' differently.

coppro
Level: Smitemaster
Rank Points: 1309
Registered: 11-24-2005
IP: Logged

I noticed it, basically. I was thinking about ways to circumvent member pointers when using C libraries, but I realized that it's completely impossible due to the technical requirement of extern "C".

EDIT: Without macros, of course, but those are evil, as we all know.

---

[Last edited by coppro at 01-08-2008 05:09 AM]

mrimer
Level: Legendary Smitemaster

Rank Points: 5106
Registered: 02-04-2003
IP: Logged

coppro wrote:
The expat callbacks used by CDbXML are static class members, but since expat is a C interface, it is nonportable to use anything but an extern "C" global function for the callbacks. I would recommend inserting just before each callback function something like:

extern "C" DbXMLCTallyElementCForward (void * ud, const char * name, const char ** atts) { CDbXml::TallyElement(ud, name, atts); }

void CDbXml::TallyElement(
...

Sure, I don't mind adding this structure, though it will generate more function calls and slow down your import procedure by a millisecond.

____________________________
Gandalf? Yes... That's what they used to call me.
Gandalf the Grey. That was my name.
I am Gandalf the White.
And I come back to you now at the turn of the tide.