Namespaced constants in C

gistfile1.m

#import <Foundation/Foundation.h>


// .h file
struct MyConstantsStruct
{
    NSString *foo;
    NSString *bar;
    int baz;
};

extern const struct MyConstantsStruct MyConstants;

// .m file
const struct MyConstantsStruct MyConstants = {
    .foo = @"foo",
    .bar = @"bar",
    .baz = 42
};

// user
int main(int argc, char **argv)
{
    [NSAutoreleasePool new];
    
    NSLog(@"%@ %@ %d", MyConstants.foo, MyConstants.bar, MyConstants.baz);
}

Variable length arrays are only available for local variables. Otherwise the compiler needs to know sizes at compile time.

Enum constants look like this:

enum
{
    kMyConstant = 42,
    kMyOtherConstant = 99
};

Of course, since enums can only be integers, this construct can only be used for integer constants.

Oh cool, I didn't know they could be assigned values. Thanks Mike, good tip. :)

ARC does not allow it... :(

ARC does allow it, but unfortunately you must put __unsafe_unretained before all of the object pointer struct members to make ARC happy.