namespaces in multiple files

[olsmokey]

if i define a namespace in file 1, and #include file 1 in file 2, how do i access the namespace in file 3... when you would use extern if it were a normal variable.

[laserlight]

hmm... why not just include file 1 in file 3?
If you have header guards in file 1 there should not be a problem.

[olsmokey]

Originally posted by laserlight
hmm... why not just include file 1 in file 3?
If you have header guards in file 1 there should not be a problem.

i tried that but i get a linker error saying that a variable is already defined.

[WaltP]

Originally posted by laserlight
hmm... why not just include file 1 in file 3?
If you have header guards in file 1 there should not be a problem.

What header guards means is in your header header.h add

#ifndef HEADER_INCLUDED
#define HEADER_INCLUDED
-- the header file
#endif

This way the header content will be included only once.

Originally posted by olsmokey
i tried that but i get a linker error saying that a variable is already defined.

Your header file should not define any variables. Only define vars in the C/CPP files.

If a variable needs to be available in more than one C file, the header can specify the variable as extern. It will then be available to all modules.