CODEWITHSUNDEEP
visual-c++
karikari
karikari

Reputation: 6807

How to pass a string to CreateProcess function?

I want to pass a string to my CreateProcess function so that I can use this function for all my operations. How to do it correctly?

Below is my code:

CString ExecuteExternalProgram(CString pictureName)
 {
   CString parameterOne = _T(" -format \"%h\" C:\\");
   CString filename = pictureName;
   CString parameterLast = _T("\"");
   CString parameterFull = parameterOne + filename + parameterLast;

   CreateProcess(_T("C:\\identify.exe"), parameterFull,0,0,TRUE,
      NORMAL_PRIORITY_CLASS|CREATE_NO_WINDOW,0,0,&sInfo,&pInfo);
   CloseHandle(wPipe);  

   .......
 }

Error:

Error 2 error C2664: 'CreateProcessW' : cannot convert parameter 2 from 'ATL::CString' to 'LPWSTR' c:\a.cpp

Upvotes: 4

Views: 3481

Answers (1)

Michael Burr
Michael Burr

Reputation: 340218

You'll need to do something like:

CreateProcess(L"C:\\identify.exe",csExecute.GetBuffer(),0,0,TRUE,
   NORMAL_PRIORITY_CLASS|CREATE_NO_WINDOW,0,0,&sInfo,&pInfo);

CreateProcess() wants a writeable buffer for the command line parameter for some reason, so the implicit conversion of CString to a plain old pointer doesn't happen (since it'll only perform the implicit conversion if it's to a const pointer).

If this isn't the problem you're running into, post more details about the error or unexpected behavior you're running into.

As an example, the following runs a little utilty program that dumps the commandline it's given:

int main() {
    CString csExecute = "some string data";

    STARTUPINFO sInfo = {0};
    sInfo.cb = sizeof(sInfo);
    PROCESS_INFORMATION pInfo = {0};

    CreateProcess(L"C:\\util\\echoargs.exe",csExecute.GetBuffer(),0,0,TRUE,
        NORMAL_PRIORITY_CLASS,0,0,&sInfo,&pInfo);

    return 0; 
}

Upvotes: 2

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