Command: define_c_proc
  
Syntax: 
  i1 = define_c_proc(a, s1, s2)
  
Description: 
  Define the characteristics of a C function that you wish to 
  call as a procedure from your Euphoria/PEU program. A small integer 
  will be returned, or -1 if the function can't be found. a is an 
  address returned by open_dll. s1 is the name of the function. 
  s2 is a list of the parameter types for the function. A list of 
  C types is contained in win32.e.
  
Comments: 
  The small integer can be passed to call_c_proc, when you want
  to call the C function.
  
  Parameter types which use 4 bytes or less are all passed the
  same way, so it is not necessary to be exact.
  
  In this alpha release of v2.0, there is currently no way to
  pass structures or doubles by value, only by a pointer to
  the value.
  
  The C function can return a value but it will be ignored.
  
Example: 
     
      -- ShowWindow is located in user32.dll
      -- It has 2 parameters that are both C int.
      ShowWindow = define_c_proc(user32, "ShowWindow", {C_INT, C_INT})
      if ShowWindow = -1 then
         puts(1, "ShowWindow not found!\n")
      end if
 
See Also: 
  define_c_proc, open_dll
  
