undefined reference to “only some math.h” functions

Question

I am having a strange problem.

The math libraries has been added to my makefile.

# include standard C library
LDFLAGS += -lc
# include standard math          


        

Answer 1

Are you including everywhere?

Notice that the names in the library are prefixed with __ieee754_, but the ones the linker can't find are not.

What happens when you compile this code?

#include 

int main(void)
{
    double d = pow(2, 3);
    double e = asin(1.0 / d);
    return (int)(e+1);
}

If the file is mathtest.c, then compile with:

gcc -o mathtest mathtest.c -lm

(Given that this fails to compile, what symbols are defined in mathtest.o?)

---

I added a comment to the main question:

Which platform are you on? Which C compiler are you using? Are you cross-compiling? What is the command line that is executed to do the linking? (I see DOS/Windows C: paths and PowerPC architecture.) Is there any chance you are using for type-generic math?

Looking at the LOAD paths you give, I see:

LOAD c:/gnu/powerpc-eabi/3pp.ronetix.powerpc-eabi/bin/../lib/gcc/powerpc-eabi/4.3.3/../../../../powerpc-eabi/lib/nof\libm.a

Which can, I think, be simplified to:

LOAD c:/gnu/powerpc-eabi/3pp.ronetix.powerpc-eabi/powerpc-eabi/lib/nof\libm.a

One part of that path that intrigues me is the nof part; could that be 'no floating point'? The other part that really intrigues me is the presence of powerpc with the c: prefix; it smacks of cross-compilation for PowerPC on a Windows platform. It is important to be forthright and explicit about such things; we need that sort of information to be able to help you sensibly.

Was this the libm.a library that you tested, or did you experiment with another file?