OpenEuphoria

Win32Lib bug

• Posted by Robert Craig <rds at RapidEuphoria.com> Feb 14, 2001
• 595 views

While testing the beta release translator, 
I came across a bug in Win32Lib.ew.

There are a couple of places where the
Windows API routines ChildWindowFromPoint() and
ChildWindowFromPointEx() are called incorrectly.

The second argument is supposed to be a POINT structure.
Euphoria does not allow you to pass a C structure by
value. You can only pass the address of a structure.
In Win32Lib.ew an attempt is made to pass the *address*
of a POINT structure, but this is not what the C routine expects.

typedef struct { 
    LONG x; 
    LONG y; 
} POINT; 

What you should do, is define an extra argument for these
routines in define_c_func(), and pass the two fields 
of the POINT structure as if they were separate arguments. 
something like:

ChildWindowFromPoint(handle, x, y)

This will push the values of x and y onto the call stack just like 
a POINT structure would be pushed, when passed by value.

There may be other cases in Win32Lib where 
it's necessary to pass a structure by value, but I
believe this not very common in the WIN32 API.

Regards,
   Rob Craig
   Rapid Deployment Software
   http://www.RapidEuphoria.com