On Feb 12, 2012, at 10:59 AM, xunxun wrote: > 于 2012/2/12 23:48, Amittai Aviram 写道: >> GDB says "No source file named omp-low.c." I also tried entering the whole absolute path instead of just the file name and got the same result. :-( All this was both before and after rebuilding with > > Try to add the file path : > break /usr/gcc/libgomp/omp-low.c:2624 That is what I did--as I said, "I also tried entering the whole absolute path instead of just the file name." BTW, note that omp-low.c is not in libgomp, it's in [GCC_ROOT]/gcc , where [GCC_ROOT] is the root directory of the gcc source tree. Amittai Amittai Aviram PhD Student in Computer Science Yale University 646 483 2639 amittai.aviram@xxxxxxxx http://www.amittai.com