linking against png 1.5

abs0 · 2011-08-22 23:24

One of the changes in png 1.5 has been to hide the internal contents of png_struct_def

xbmc/lib/cximage-6.0/CxImage/ximapng.{cpp,h} use png_struct_def directly when setting up a customer error handler:

ximapng.cpp

Code:

png_set_error_fn(png_ptr,info.szLastError,/*(png_error_ptr)*/user_error_fn,NULL);

ximapng.h

Code:

static void PNGAPI user_error_fn(png_structp png_ptr,png_const_charp error_msg)

        {

                strncpy((char*)png_ptr->error_ptr,error_msg,255);

                longjmp(png_ptr->jmpbuf, 1);

        }

Its not entirely clear what is going on here - it looks like user_error_fn() is setup to pretty much reproduce png_error(), but without displaying any message to stderr. What is curious is that the png_set_error_fn() only ovverrides png_warning(), not png_error(), so any call to png_warning() will still be echoing content to stderr, plus ximapng.h calls png_error() directly in some cases.

Am I missing anything obvious where - why is user_error_fn() needed at all?

Thanks

**spiff** · 2011-08-23 11:21

probably xbox leftovers - we had no cout/cerr there...

abs0 · 2011-08-23 11:34

spiff Wrote:probably xbox leftovers - we had no cout/cerr there...

OK thanks. Those files are full of direct png_struct_def usage - will try to take a pass through to update them all to the approved png API calls, and just drop the png_set_error_fn() usage...

spiff Grumpy Bastard Developer Posts: 12,187 Joined: Nov 2003 Reputation: 82	2011-08-23 11:21 Post: #2 probably xbox leftovers - we had no cout/cerr there... Always read the XBMC online-manual, FAQ and search the forum before posting. Do not e-mail XBMC-Team members directly asking for support. Read/follow the forum rules. For troubleshooting and bug reporting please make sure you read this first.
	find quote

abs0 Junior Member Posts: 12 Joined: Jun 2011 Reputation: 0 Location: London	2011-08-23 11:34 Post: #3 spiff Wrote:probably xbox leftovers - we had no cout/cerr there... OK thanks. Those files are full of direct png_struct_def usage - will try to take a pass through to update them all to the approved png API calls, and just drop the png_set_error_fn() usage...
	find quote