I am trying to use CreateProcess to start a new environment block and run a batch file in the new environment block. I've read through the msdn example for CreateProcess, and came up with the code shown below.
What is happening, it will open the new command prompt, and stop there. It will not run my .bat file for some reason. Using system("CALL path") will call the .bat file.
#include <iostream>
#define WINDOWS_LEAN_AND_MEAN
#include <Windows.h>
#include <strsafe.h>
#define BUFSIZE 4096
int main()
{
//system("CALL C:\\HFSS\\setup_vars.bat");
//return 0;
LPWCH chNewEnv;
LPTSTR lpszCurrentVariable;
DWORD dwFlags = 0;
TCHAR szAppName[] = TEXT("C:\\windows\\system32\\cmd.exe");
TCHAR cmdArgs[] = TEXT("C:\\HFSS\\setup_var.bat");
STARTUPINFO si;
PROCESS_INFORMATION pi;
BOOL fSuccess;
// Copy environment strings into an environment block.
chNewEnv = GetEnvironmentStrings();
lpszCurrentVariable = (LPTSTR)chNewEnv;
if (FAILED(StringCchCopy(lpszCurrentVariable, BUFSIZE, TEXT("MySetting=A"))))
{
printf("String copy failed\n");
return FALSE;
}
lpszCurrentVariable += lstrlen(lpszCurrentVariable) + 1;
if (FAILED(StringCchCopy(lpszCurrentVariable, BUFSIZE, TEXT("MyVersion=2"))))
{
printf("String copy failed\n");
return FALSE;
}
// Terminate the block with a NULL byte.
lpszCurrentVariable += lstrlen(lpszCurrentVariable) + 1;
*lpszCurrentVariable = (TCHAR)0;
// Create the child process, specifying a new environment block.
SecureZeroMemory(&si, sizeof(STARTUPINFO));
si.cb = sizeof(STARTUPINFO);
#ifdef UNICODE
dwFlags = CREATE_UNICODE_ENVIRONMENT;
#endif
fSuccess = CreateProcess(szAppName, cmdArgs, NULL, NULL, TRUE, dwFlags,
(LPVOID)chNewEnv, // new environment block
NULL, &si, &pi);
if (!fSuccess)
{
printf("CreateProcess failed (%d)\n", GetLastError());
return FALSE;
}
std::cout << "In new environment\n";
WaitForSingleObject(pi.hProcess, INFINITE);
return TRUE;
}
Some problems:
/C
option tocmd.exe
in order to make it execute the .bat file.CreateProcess
must be a modifiable string. Not a literal.lpszCurrentVariable
points to the buffer returned byGetEnvironmentStrings
. You cannot modify that buffer. You need to allocate a new buffer of sufficient length and copy the environment into it. Then add your modifications.StringCchCopy
rather than C runtime functions is just confusing. Don't take MSDN example code as being the paragon of style.std::wstring
and other standard library classes and function.WINDOWS_LEAN_AND_MEAN
before importingWindows.h
.int main(void)
is incorrect. The no argumentmain
isint main()
.The following code shows you how to do this: