Weird XCode error - baffled :S

You haven't declared the function prototypes for those functions, or if they are library functions included the relevant header files.

 

The compiler doesn't know where that function is at that point, so you need to declare it before the main() function:

Code:

void someFunction();

You could use a header but for this example it's unnecessary.

BTW this is a C issue, not Obj-C, although you can run into the same issue with methods once you get into classes.

 

This isn't really a fix. Get used to always declaring function prototypes.

 

The solution has already been posted but to help you understand further the "conflicting types" error message, when you reference a function that hasn't already been previous declared, the compiler has to make a guess at what it does (hence the warning, "implicit declaration of function").

I believe the compiler assumes implicit functions to return type int, so when you declare your functions later in the file with a different return type to int, that is why you get the conflicting types error.

 

Is it really such a big deal to simply declare functions at the top of the file if they are internal/private to that file?

 

Sure, but if they are internal / private to the file they should be declared as static functions.

Still it is worth using function prototypes rather than relying on the order of the functions because that is going to cause problems down the road when you insert some code and it doesn't work.