linking pgi compiled library with gcc linker

Question

I would like to know how to link a pgc++ compiled code (blabla.a) with a main code compiled with c++ or g++ GNU compiler. For the moment linking with default gnu c++ linker gives errors like: undefined reference to `__pgio_initu'

Answer 1

As the previous person already pointed out, PGI supports G++ name mangling when using the pgc++ command. Judging from this output, I'm guessing that you're linking with g++ rather than pgc++. I've had the most success when using pgc++ as the linker so that it finds the PGI libraries. If that's not an option, you can link an executable with pgc++ -dryrun to get the full link line and past the -L and -l options from there to get the same libraries.

Answer 2

Different C++ compilers use different name-mangling conventions to generate the names that they expose to the linker, so the member function name int A::foo(int) will be emitted to to the linker by compiler A as one string of goobledegook, and by compiler B as quite a different string of goobledegook, and the linker has no way of knowing they refer to the same function. Hence you can't link object files produced by different C++ compilers unless they employ the same name-mangling convention (and quite possibly not even then: name-mangling is just one aspect of ABI compatibility.)

That being said, according to this document, PGC++ supported name-mangling compatibility with g++ 3-and-half years ago, provided that PGI C++ compiler was invoked with precisely the command pgc++ or pgcpp --gnu. It may be that the library you are dealing with was not built in that specific way, or perhaps was built with an older PGI C++ compiler.

Anyhow, if g++ compiles the headers of your blabla.a and emits different symbols from the ones in blabla.a, you can't link g++ code with blabla.a. You'd need to rebuild blabla.a with g++, which perhaps is not an option.