> I am trying to change some source files in the GCC compiler and > getting a compilation error. > > In the file "gimple.h", I am adding > > extern int x; // the x is global and should be accesable from other > files as well. > > > Then I called x in the "tree_into_ssa.c". However, when I compile the > gcc compiler using the make command I get the following massage: > > undefined refernce to "x". > > > Any comments??? First, this is really a general programming question, and this mailing list is more for gcc-specific issues. In future, try a general programming forum like at http://www.linuxquestions.org/questions/programming-9/. This error occurs because "extern int x" declares a variable called x, but does not define it - you need to define it (exactly once) with "int x" in a source file that will be linked in with whatever source files you want to use it in. If you don't know the difference between declaring and defining a variable, I suggest you get a good C book and have a thorough read. John G
