Warning: assignment makes pointer from integer without cast undefined

Question

I understand that there are many questions related to this problem, but I could not make a chapter and a story from those that I read.

I am trying to start learning C for Amiga and decided to try this tutorial: http://www.pcguru.plus.com/tutorial/amiga_c.html

Upon reaching this point, I already run into noob problems:

#include <proto/intuition.h> #include <intuition/screens.h> #include <proto/dos.h> #include <stdio.h> int main(void) { struct Screen *myScreen; if (myScreen = LockPubScreen(NULL)) { printf("Public Screen locked.\n"); Delay(100); UnlockPubScreen(NULL, myScreen); printf("Public Screen unlocked.\n"); } return 0; } 

I use the GCC compiler with the following command from the shell:

 gcc -o LockPubScreen LockPubScreen.c 

This returns the following:

 Warning: assignment makes pointer from integer without a cast undefined reference to 'LockPubScreen' undefined reference to 'Delay' undefined reference to 'UnlockPubScreen 

Apart from "HelloWorld", this is the first attempt at either C or Amiga programming, so I assume that I will miss something obvious.

Answer 1

You probably need to include one or more of these additional files to get a prototype for functions that you are missing:

 #include <intuition/gadgetclass.h> #include <intuition/IntuitionBase.h> #include <libraries/gadtools.h> #include <clib/exec_protos.h> #include <clib/intuition_protos.h> #include <clib/gadtools_protos.h> 

Then, as NPE suggests, there may be a problem with link errors if your compiler does not include a props library by default, and if you do not specify one.

Answer 2

If you mentioned that you tried to compile the program for AmigaOS 4.x, the answer would be obvious. The library function call in OS4 should also contain the library interface - IIntuition-> LockPubScreen (), IDOS-> Delay (), etc. - or you must #define __USE_INLINE__ at the beginning of the code.