Amittai Aviram <amittai.aviram@xxxxxxxx> writes: > int global_a, global_b; In C, by default, these are common symbols. They won't be defined in the .bss section of the .o file. If the linker does not see another definition, it will eventually allocate them in the .bss section, but this will be independent of your head.s and tail.s files. You can change this behaviour with gcc's -fno-common option, q.v. > (a) my_data_start is missing, only my_data_end appears. (If, however, > I only include head.o in my Makefile,rule, then my_data_start appears > in the location where my_data_end appears in the above extract.) I think my_data_start is missing because of the way you are examining the .o file. There are two symbols at the address of my_data_start--my_data_start and the first symbol in the .bss section. objdump -D happens to be showing you just one of them. Use readelf -s or objdump -t or nm. > (b) my_data_end is separated from global_a and global_b and seems to be in an arbitrary location in relation to them. That's because they are common symbols. Ian
