A problem with using xdb

I tried to use xdb to debug a unix c++ program. However, I got an error message saying that "It appears that there is no debugging information in MyProgram No core file". Actually, I already specify "-g" option for the c++ compiler. Does anybody tell me why the debugging failed? Thanks a lot.
[294 byte] By [dullboy] at [2007-11-19 1:49:08]