How to view symbols in object files?

Question

How can I view symbols in a .o file? nm does not work for me. I use g++/linux.

Answer 1

There is a command to take a look at which functions are included in an object file or library or executable:

nm

Answer 2

Instead of nm, you can use the powerful objdump. See the man page for details. Try objdump -t myfile or objdump -T myfile. With the -C flag you can also demangle C++ names, like nm does.

Answer 3

Just run: nm you_obj_file.o | c++filt

Answer 4

Have you been using a cross-compiler for another platform? If so, you need to use the respective nm or objdump commmand.

For example, if you have used XXX-YYY-gcc to compile the .o file, you need to use XXX-YYY-nm or XXX-YYY-objdump to process the files.

Answer 5

You can use nm -C .o/lib/exe, for example:

xiongyu@ubuntu:~/tmp/build$ nm -C libfile1.a 

file1.cpp.o:
0000000000000000 T f()
0000000000000000 W int fun<int>(int)

using nm -C it will be more readable, if you just use nm:

xiongyu@ubuntu:~/tmp/build$ nm libfile1.a 

file1.cpp.o:
0000000000000000 T _Z1fv
0000000000000000 W _Z3funIiET_S0_

as we see it's not so readable.

Below is what my file1.cpp like:

xiongyu@ubuntu:~/tmp/build$ vi ../file1.cpp 
#include "head.h"
void f()  {
     int i = fun<int>(42);
}