View Full Version : Linking assembly functions into C++ using g++

November 19th, 2007, 07:40 AM
Hey guys. I'm working on a medium-sized C++ program that requires a bit of an assembly back-end to tinker with the stack. I've got a bunch of .cpp files that reference an assembly function defined in a .s file elsewhere. I can use gcc to compile the .s into a .o without any problems, but am not sure exactly how I can link the assembly function it defines so my other files can use it... I've tried the obvious:

g++ -lassemblyCode.o cppCode.cpp
but the compiler complains about missing functions. For regular C++ functions, I'd avoid this by using header files, but unfortunately in this case I can't. If it matters, this is to be compiled on a SPARC system so the inline __asm__ directives are kind of out the door, to be replaced with code like this:

.seg "text"
.proc 4
.global _assembly_function:
//do work

How can I get this assembly code from a .s file as a working function in C++?

Thanks for any help.

Lux Perpetua
November 19th, 2007, 07:52 AM
You need to declare your assembly language functions in your C++ code as
extern "C"Then you can link the object file normally with your C++ file. By the way, you don't need "-lassemblyCode.o".
g++ assemblyCode.o cppCode.o

November 19th, 2007, 05:35 PM
Awesome, this worked nicely. Thanks for the help!