why compile header files

[cspears]

I've been teaching myself C++. Why do you need to compile .h files in order to use them? I thought these files are just being read.

[madcompnerd]

You shouldn't be compiling them.

[cspears]

For some reason, my code didn't work until I compiled them.

[evac-q8r]

Your are right... the files are read by the include statement and then are expanded within the .c file that includes it.

EVAC

[truls]

What exactly do you mean by "compiled them"?

Could you please post the makefile, or the command line you are using to compile the program. Do you mean include them?

[cspears]

I first used this:

g++ Employee.h

Then I did this:

g++ -o MakeAnEmployee MakeAnEmployee

[madcompnerd]

Have you defined any objects in your .h files?

void foo(void);
Is not an object.

void foo(void)
{
printf("foo!");
}
Is an object.


struct bar
{
int j;
};
Is not an object.

struct bar *x = (struct bar *)malloc(sizeof(struct bar));
Is an object.

You must compile objects, but not headers. Objects should only exist in your .c files.
Don't get thrown off by my use of the word object, I'm aware this is c and not c++. I couldn't think of a better word to describe a defined element verse a note that a element will be later defined.

[madcompnerd]

Are you including other project files in your .h? You should never include anything but .h files as a general rule.

[cspears]

Employee.h is the header file referenced by MakeAnEmployee. You probably have figured this out, but I decided to clarify it for others. Employee.h contains a class, which I think is an object, right? That is probably why I needed to compile it.