c# - Access violation on c++ methods launched from DllImport -


i have strange problem methods, launched dllimport.

in native c++ have code:

#define bufsize 4096  int _tmain(int argc, _tchar* argv[]) {     wchar_t *tekst = l"d:\\matiz\\dokumenty\\!firma trim-pot\\firmowe";     printtekst(tekst); }  bool printtekst(wchar_t *tekst) {        dword  retval = 0;     bool   success;     tchar  buffer[bufsize] = text("");     tchar  buf[bufsize];     tchar** lpppart = { null };     retval = getfullpathnamew(tekst, bufsize, buffer, lpppart);     return true; }  bool __stdcall printtekstextern(wchar_t *tekst) {     return printtekst(tekst); }

when call printtekst method direct main function ok, when call method using dllimport, on line:

tchar  buffer[bufsize] = text("");

i have access violation exception. it's strange situation, because in fact don't use arguments, come manager code in case.

method, launched in c#:

[dllimport("pointers.exe", callingconvention = callingconvention.stdcall, charset = charset.auto)] public static extern bool printtekstextern(string tekst);  static void main(string[] args) {     string cos = @"d:\matiz\dokumenty\visual studio 2013\projects\pointers\pointerssharp\bin\debug";     var status = printtekstextern(cos); }

}

could me?

the big problem trying import function executable rather dll. that's first thing fix, , real cause of fatal crash.

beyond that, unmanaged function is:

bool __stdcall printtekstextern(wchar_t *tekst)

your p/invoke is:

[dllimport("...", callingconvention = callingconvention.stdcall,      charset = charset.auto)] public static extern bool printtekstextern(string tekst);

there 1 minor problem here. return value marshalled 4 byte boolean type, unmanaged code uses 1 byte type. read here: http://blogs.msdn.com/b/jaredpar/archive/2008/10/14/pinvoke-and-bool-or-should-i-say-bool.aspx

fix changing p/invoke so:

[dllimport("...", callingconvention = callingconvention.stdcall,      charset = charset.auto)] [return: marshalas(unmanagedtype.u1)] public static extern bool printtekstextern(string tekst);

i suggest using charset.unicode since unmanaged code uses wchar_t , therefore explicit using 16 bit text.


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