Hello, I tried using pahole, but I get a brain fart alert with the file attached (which is an extract from stdio.h). I'm running dwarves 1.10, libdw1 0.152 and g++ 4.6.1, on i386. Here is what I get: $ g++ -Wall -g -c brainfart.cpp -o brainfart.o && pahole brainfart.o class ios_base { enum _Ios_Openmodeconst in; /* 0 4 */ typedef enum _Ios_Fmtflags fmtflags; /* size: 1, cachelines: 1, members: 1 */ /* padding: 65533 */ /* last cacheline: 1 bytes */ /* BRAIN FART ALERT! 1 != 4 + 0(holes), diff = -3 */ }; Moreover, on amd64, pahole segfaults if I do the same (with dwarves 1.10, libdw1 0.152, g++ 4.6.3). Any ideas? Thanks a lot, Nicolas