global variable in PhAB

QNX DEVELOPERS GUI Programming
1

where can you declare your global variable in PhAB so that all your callback functions can have access to it?

Thanks

2

See the “Global header file” section in the Working with Code chapter of the Photon Programmer’s Guide.

3

thanks will do~

4

I have read the documents and tried it but it’s not working. Here is my global.h file

#include <Pt.h>
#ifdef DEFINE_GLOBALS
#define GLOBAL
#define INIT(x) = x
#else
#define GLOBAL extern
#define INIT(x)
#endif
//global variables
GLOBAL int number INIT(0);

in only one of my callback function, I have added
#define DEFINE_GLOBALS
but when I try to use the number variable in any of my callback functions I get undefined error message during compile time. I have added global file information in PhAB and it seemed to generate the correct code in momentics. Any ideas? Do I have to define the “DEFINE_GLOBALS” in some specific callback function?

5

The #define DEFINE_GLOBALS needs to be in the include of global.h and not in the function.

Personnaly I don’t like this trick of having a single line of code be both definition for extern and declaration though a #define. Instead have global.h always define extern and put the variable somewhere in a C file (I like to create a global.c file or if applicable put it in the main.c )

6

Thanks a bunch~