Thread: header files

I've got a question : Is it good to use :

Code:

#indef SOMETHING_H
#deinfe SOMEHING_H
... put your class here ...
#endif

Since if you include the header two times you don't get an error. But it seems that with this kind of protection you can include header only once, and every time you try to do it again the compiler ignores it, which prevents tracking bugs.

Isn't it better to include the headers properly without using that above, and if you make a mistake the compiler warns you and you correct it.

So do you use that above. To me it seems stupid ? Can you explain me why i'm wrong ?

You can avoid it, but you have to be VERY careful about the order in which you include files.

Also, if foo.h depends on bar.h, then you have to manually include bar.h BEFORE foo.h in all the places foo.h is included.

In a large project, this kind of restriction can result in pages of #include at the beginning of each file and a maintenance nightmare.

Originally Posted by ElastoManiac

Code:

#deinfe

Yeah, it would work if it was spelled right

Not to mention ifdef and the same macro name . . .

and every time you try to do it again the compiler ignores it,

. . . true . . .

which prevents tracking bugs.

false -- it's already been included into the file. If it would generate an error, the first instance would generate an error too.

Originally Posted by ElastoManiac

Since if you include the header two times you don't get an error. But it seems that with this kind of protection you can include header only once, and every time you try to do it again the compiler ignores it, which prevents tracking bugs.

What kind of bug would it hide or prevent you from tracking?

ElastoManiac, check google for "C++ ODR headers guards". ODR stands for One Definition Rule.