Question

How can I know in which step (Pre-Processor,Compiling, Linking) my program got compilation failure?

For example, I wrote a program of 3 source files: a.c ,b.c, c.c and all three of them included the header file, h.h, which contains all the prototypes of all the source files, but I also implemented one function, in the header file. I know it’s wrong to do, but I wonder on what stage did the program crash, Is it the linking or the compiling, I got an error message, Is this say that the problem is at the linking stage? (otherwise I’ll just get a red underline on the mistake from the compiler?)

Where can I read about linking and what I shouldn’t do regarding headers and source files and linking errors?

(I work in Linux, with Eclipse)

Answer 1

You find the location of the error by separating compiling and linking. An error due to the precompiler is unusual and also found during compiling. This is how compiling works on the command line:

Compile step:

gcc -c -o a.o -pedantic -Wall a.c 
gcc -c -o b.o -pedantic -Wall b.c 
gcc -c -o c.o -pedantic -Wall c.c 

link step:

gcc a.o b.o c.o -o prog

Of course you need to specify whatever other flags that are necessary (e.g. -l for linking to a library etc.)

Then read the errors and warnings (!) carefully and you shall find the problem.