What does the “undefined reference to varName” in C mean?

Question

I have 2 files: a.c and b.c

In a.c I am sending a signal to a function located in b.c

signal(SIGU         


        

Answer 1

You need to compile and then link the object files like this:

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