Search:

Wait, does OP need a function to create the variable? I thought we were doing
header:


extern double phys_MO;

one C file:


double phys_MO = 4.29496E-6;

One time. If you don't put extern on it in the header, then you're declaring it a lot of times -- one time every time you #include the header.

I'll bet you a nickel that you now have two .o files in that directory. And also, if you put int X=5 in your two.c file you'd get different answers.

EDIT: Nope, I'm wrong. GCC doesn't write out...

You should look at the word "extern".