c_proc
| Definition: | c_proc(integer rid, sequence args={}) |
| Description: |
Call a C function.
rid must be a result from define_c_proc(). args is a sequence of argument values of length n, where n is the number of arguments required by the function. |
| pwa/p2js: | Not supported. |
| Comments: |
If the C routine does not take any arguments then args should be {}.
If you pass an argument value which contains a fractional part, where the C function expects a C integer type, the argument is be rounded towards 0, for example 5.9 is passed as 5, -5.9 is passed as -5. The C function could be part of a .dll or .so created via a format DLL/SO directive. NB: While call_proc(id,args) can now be invoked via id(args), you cannot replace c_proc(rid,args) with rid(args). |
| Example: |
atom hwnd, pRect = allocate_struct(idRect)
atom user32 = open_dll("user32.dll")
-- GetClientRect is a VOID C function that takes a C int
-- and a C pointer as its arguments:
integer GetClientRect = define_c_proc(user32, "GetClientRect", {C_INT, C_PTR})
-- pass hwnd and rect as the arguments
c_proc(GetClientRect, {hwnd, pRect})
|
| Implementation: | See builtins\VM\pcfunc.e (an autoinclude) for details of the actual implementation. |
| See Also: | c_func, define_c_proc, open_dll, Calling C Functions |