When you compile a program with "-pg" against libexpat 1.95.8 and you call XML_ParserCreate() it does crash. this is not happening, if you don't add "-pg".
The source I used was distributed with the official MAME source code package (http://www.mame.net/downmain.html - win32 sourcecode, but the related source should be platform-independent). The easiest way to test it, is just to compile the "xml2info" tool, that part is of MAME, add "-pg" to compiler and linkers flags and run it, it will crash immediately. Here is the backtrace: Program received signal SIGSEGV, Segmentation fault. 0x0040e456 in poolInit (pool=0x40e44d, ms=0x0) at src/expat/xmlparse.c:5874 5874 pool->blocks = NULL; (gdb) bt #0 0x0040e456 in poolInit (pool=0x40e44d, ms=0x0) at src/expat/xmlparse.c:5874 #1 0x0040d339 in dtdCreate (ms=0x3f2554) at src/expat/xmlparse.c:5428 #2 0x00403193 in parserCreate (encodingName=0x0, memsuite=0x0, nameSep=0x0, dtd=0x0) at src/expat/xmlparse.c:737 #3 0x00402fb7 in XML_ParserCreate_MM (encodingName=0x0, memsuite=0x0, nameSep=0x0) at src/expat/xmlparse.c:671 #4 0x00402f4b in XML_ParserCreate (encodingName=0x0) at src/expat/xmlparse.c:648 #5 0x00402b7c in process (is=0x7803a690, os=0x7803a6b0) at src/xml2info.c:766 #6 0x00402efe in main (argc=1, argv=0x3f24c8) at src/xml2info.c:835 My GCC version: Reading specs from C:/MINGW/BIN/../lib/gcc/mingw32/3.4.2/specs Configured with: ../gcc/configure --with-gcc --with-gnu-ld --with-gnu-as --host= mingw32 --target=mingw32 --prefix=/mingw --enable-threads --disable-nls --enable -languages=c,c++,f77,ada,objc,java --disable-win32-registry --disable-shared --e nable-sjlj-exceptions --enable-libgcj --disable-java-awt --without-x --enable-ja va-gc=boehm --disable-libgcj-debug --enable-interpreter --enable-hash-synchroniz ation --enable-libstdcxx-debug Thread model: win32 gcc version 3.4.2 (mingw-special) -- Summary: -pg causes libexpat code to crash Product: gcc Version: 3.4.2 Status: UNCONFIRMED Severity: normal Priority: P2 Component: gcov/profile AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: oliverst at online dot de CC: gcc-bugs at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21810