OpenEuphoria

1. Ver. 40 Serious Error/Bug

• Posted by bernie Oct 04, 2008
• 952 views

There is a serious Bug in the code. 
I'am using WIN98 SVN rev. 1191 and do not know if same problem 
happens in other operating systems. 
If You run the following simple program you should be able to 
duplicate the failure of call_back(). 
 
 
-- ================== begin JUNK.EXW ======================= 
 
-- This is the simplest example that I can give from my code. 
 
include std/dll.e 
 
integer i1 = define_c_func(open_dll("user32.dll"),"MessageBeep", 
					   {#2000004}, #1000004) 
 
? c_func(i1,{#40}) -- call the function with MB_ICONASTERISK parameter. 
 
-- This should print a callback address and it did work in the past. 
-- Note it is using the same routine_id value that was used in the above 
-- call which will work. 
-- 
-- This does not work but returns a bad routine id error ! 
? call_back(i1) 
 
if getc(0) then end if -- pause() 
 
-- ================== end JUNK.EXW ======================= 

3. Re: Ver. 40 Serious Error/Bug

• Posted by jimcbrown (admin) Oct 04, 2008
• 925 views

The correct way to get a function pointer/memory address for a C routine is this code:

include std/dll.e 
 
integer i1 = define_c_func(open_dll("user32.dll"),"MessageBeep", 
					   {#2000004}, #1000004) 
atom i1_callback = define_c_var(open_dll("user32.dll"),"MessageBeep") 
 
? c_func(i1,{#40}) -- call the function with MB_ICONASTERISK parameter. 
 
? i1_callback 
 
if getc(0) then end if -- pause() 

define_c_var() works on functions, returning a function pointer (the same thing as call_back() returns), as well as its normal use to return a pointer to a C variable.

include std/dll.e 
 
integer i1 = define_c_func(open_dll("user32.dll"),"MessageBeep", 
					   {#2000004}, #1000004) 
 
? c_func(i1,{#40}) -- call the function with MB_ICONASTERISK parameter. 
 
? call_back(i1) 
 
if getc(0) then end if -- pause() 

5. Re: Ver. 40 Serious Error/Bug

• Posted by bernie Oct 04, 2008
• 916 views

include std/dll.e 
 
integer i1 = define_c_func(open_dll("user32.dll"),"MessageBeep", 
					   {#2000004}, #1000004) 
atom i1_callback = define_c_var(open_dll("user32.dll"),"MessageBeep") 
 
? c_func(i1,{#40}) -- call the function with MB_ICONASTERISK parameter. 
 
? i1_callback 
 
if getc(0) then end if -- pause() 

Thanks Jim:

I knew about that but I got hung up on beleaving what the library doc said.