How to start an external program from service [duplicate] - c++

Question

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c++ get registry key returns only one char
(1 answer)
Closed 9 years ago.
I am trying to invoke a binary from a service program. The path of the binary is fetched from a registry key. The path only contains "C" when I assign the buffer to the string. Where am I commiting the mistake. I am using visual studio 2010Here is the code:
std::string path;
getPathFromKey(path);
path = path+"\\myapp.exe";
argument = "start \"\" \""+path+"\"";
system(argument.c_str());
/* retrieving key */
void getPathFromKey(std::string &path)
{
HKEY hKey = 0;
char buf[512];
DWORD dwType = 0;
DWORD dwBufSize = sizeof(buf);
if( RegOpenKey(HKEY_LOCAL_MACHINE,L"SOFTWARE\\MYAPP\\MyApp",&hKey) == ERROR_SUCCESS)
{
dwType = REG_SZ;
if( RegQueryValueEx(hKey,L"InstallPath",0, &dwType, (LPBYTE)buf, &dwBufSize) == ERROR_SUCCESS)
{
for(int i=0;buf[i];i++)
path[i]=buf[i];
return;
}
else
{
RegCloseKey(hKey);
return;
}
}
else if( RegOpenKey(HKEY_LOCAL_MACHINE,L"Software\\Wow6432Node\\MYAPP\\MyApp",&hKey) == ERROR_SUCCESS)
{
dwType = REG_SZ;
if( RegQueryValueEx(hKey,L"InstallPath",0, &dwType, (BYTE*)buf, &dwBufSize) == ERROR_SUCCESS)
{
for(int i=0;buf[i];i++)
path[i]=buf[i];
return;
}
else
{
RegCloseKey(hKey);
return;
}
}
}
I get the following error:
Windows cannot find "C"

Answer 1

If you get letter C, that means your code is partially working. However, this:
for(int i=0;buf[i];i++)
path[i]=buf[i];
makes no sense, at least not for me, because I can't even image how this cycle would work (given that you get letter C probably means that it runs once). A simple solution would be to use this:
path = std::string(buf);
If I am wrong then check buf value before return, while debugging.