accessing win32 c/c++ struct members c#

i am intercepting win32 api calls internal dll exe doing c# controlling kind hooking. sole box i am prying drawtext() user32.dll. announced win32 api:

int winapi drawtextw(hdc hdc, lpcwstr str, int count, lprect rect, uint flags)

the lprect struct following signature (also win32 api):

typedef struct tagrect { 
    enlarged left;
    enlarged top;
    enlarged right;
    enlarged bottom;
} rect lprect;

long typedef 32bit integers 32bit systems (don't know 64bit systems, irrelevant during indicate since i am 32bit windows). means opening members struct i announced c# code...

[structlayout(layoutkind.sequential, container = 1)]
    open struct rect
    {
        open int32 left;
        open int32 top;
        open int32 right;
        open int32 bottom;
    }

... wrote signature p/invoke controlling rect struct:

[dllimport("user32.dll", charset = charset.unicode, setlasterror = true, callingconvention = callingconvention.stdcall)]
static extern intptr drawtext(intptr hdc, twine str, int32 count, ref rect rect, uint32 flags, intptr dtp);

since structs value forms c# opposing being anxiety forms c/c++, ref modifier required here.

however i rect.top rect.left etc, roughly always relapse 0. i know fact incorrect. nonetheless after googling large hours perplexing lot opposite things, i couldn't rudimentary things work.

things i've tried:

• using opposite primitives rect members (int, long, short, uint32...). indeed kinda apparent form problem since any box i should stammering numbers, 0.


• removing ref modifier. also ridiculous (desperate times, unfortunate measures) since rect.left justly advantage pointer rect instead the value.


• tried unsafe formula blocks. didn't work nonetheless i competence have finished mistake doing (i don't remember i've done). besides proceed generally indifferent machiavellian pointer situations com win32, profusion box anyway.


• tried adding [marshallas] before members rect. finished difference.


• played around pack values. difference.

i am sincerely certain i'm blank something unequivocally easy candid nonetheless i have thought is...

any assistance appreciated. conclude you.