CODEWITHSUNDEEP
c++winapicreateprocess
schwing
schwing

Reputation: 11

run external .exe via c++

what i tried to do: do start an external .exe file (which is compiled from fortran) on windows via another c++ program

I have tried many different versions, like:

system("C:/IPSE_temp/CEA_schwing.exe");

compiling was ok, but when i executed the file he missed some libraries such as RUND32.dll...

Then i tried to use this kind of code (CreateProcess) in different variations

std::string rt = "C:/IPSE_temp/CEA_schwing.exe";

STARTUPINFO info = { sizeof(info) };
PROCESS_INFORMATION processInfo;

if (CreateProcess(NULL, (LPWSTR) rt.c_str(), NULL, NULL, TRUE, 0, NULL, NULL, &info, &processInfo);)
    {
    WaitForSingleObject(processInfo.hProcess, INFINITE);
    CloseHandle(processInfo.hProcess);
    CloseHandle(processInfo.hThread);
    }

cause i wanna know too, when the program is finished (program should wait until external .exe has finished it's work). Compiling was ok, but he never runs the .exe

I hope that i skipped nothing in de description, an i'm looking forward to your help. Thanks in advance

And yes, i'm new into programming in c++ ;)

best regards

hanks to Barmak Shemirani, the program is now running.

unfortunately there is an additional error:

my CEA_schwing.exe is reading a file "SINGLE_TP.inp" from the same directory. this is working fine wenn i run die exe through the windows explorer.

But by running the .exe through my c++ program, he isn't able to find the file anymore. Does anybody know why he doesn't get the file anymore?

Upvotes: 1

Views: 4894

Answers (1)

Barmak Shemirani
Barmak Shemirani

Reputation: 31599

rt.c_str() should be the first parameter in CreateProcess().

Moreover, you are mixing ANSI and Unicode. You are clearly compiling for Unicode, where CreateProcess() maps to CreateProcessW(). std::string contains char data, so c_str() returns a const char * pointer, but CreateProcessW() is expecting a wchar_t* pointer instead. Casting with (LPWSTR)rt.c_str() will simply hide the compiler error, but it doesn't fix the actual problem of you passing ANSI data where Unicode data is expected.

Use a wide string instead when declaring Unicode strings (Note the L prefix):

std::wstring rt = L"C:/IPSE_temp/CEA_schwing.exe";
if (CreateProcess(rt.c_str(), NULL, NULL, NULL, TRUE, 0, NULL, NULL, &info, &processInfo))
...

That works because rt.c_str() is now compatible with the first parameter of CreateProcess(), which is an LPCWSTR and will accept a const wchar_t * pointer from c_str() (the second parameter does not accept a const pointer).

Alternatively, you can declare wchar_t buf[MAX_PATH] and use it as the second parameter in CreateProcess(), which is of type LPWSTR (non-const):

wchar_t buf[MAX_PATH];
wcscpy_s(buf, L"C:/IPSE_temp/CEA_schwing.exe");
CreateProcess(0, buf, ...);

You can also set the working directory in the 8th parameter:

wchar_t buf[MAX_PATH];
wcscpy_s(buf, L"C:\\IPSE_temp\\CEA_schwing.exe");

std::wstring dir = L"C:\\IPSE_temp";
CreateProcess(0, buf, NULL, NULL, TRUE, NORMAL_PRIORITY_CLASS, NULL, dir.c_str(), &si, &pi);

Upvotes: 4

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