Linker warnings from wscc

Question

I am building a Mathematica interface to my c++ program. My makefile and source are available at github. This is the line that invokes wscc,

wscc -b64 -o math.exe math.tm math.c thermal_funcs.o zeta.o -lgsl -lgslcblas $(MATH_INC)

The *.o object files are linked successfully and math.exe is built by wscc. However, during the compilation stage, it appears that the object files are still passed to my C-compiler (they should only be passed during linking), such that I receive warnings:

math.c: gcc: warning: thermal_funcs.o: linker input file unused because linking not done
gcc: warning: zeta.o: linker input file unused because linking not done
math.exe.tm.c: gcc: warning: thermal_funcs.o: linker input file unused because linking not done
gcc: warning: zeta.o: linker input file unused because linking not done

I guess they are innocuous and the resulting executable math.exe works as expected. You can produce similar warnings by running

gcc -c test.c test.o

upon emtpy files test.c and test.o It seems like a (fairly harmless) bug in wscc, as it shouldn't be passing object files to gcc -c commands. But maybe I am doing something wrong?

Answer 1

In your src/makefile, on the line that contains $(MATH) -b64 ..., change "thermal_funcs.o zeta.o" to "-Wl,thermal_funcs.o,zeta.o" That's a lowercase ell after the W, not the digit 1.

And, then, of course, make math.exe

The man page for gcc describes linker options. "-Wl,options" is a way of passing options directly to the linker. I don't know any more than that.

I tried your makefile, and got the two error messages. Then I tried "-Wl,options" and the error messages went away.