C++ Getting UTF-8 output from CreateProcess() - c++

Question

I can't make it work so I get UTF-8 output from CreateProcess() into wstring.
Currently I am running this method to do that but without UTF-8 output:
HANDLE g_hChildStd_OUT_Rd = NULL;
HANDLE g_hChildStd_OUT_Wr = NULL;
HANDLE g_hChildStd_ERR_Rd = NULL;
HANDLE g_hChildStd_ERR_Wr = NULL;
PROCESS_INFORMATION CreateChildProcess(void);
void ReadFromPipe(PROCESS_INFORMATION);
string run(char *command){
SECURITY_ATTRIBUTES sa;
sa.nLength = sizeof(SECURITY_ATTRIBUTES);
sa.bInheritHandle = TRUE;
sa.lpSecurityDescriptor = NULL;
if ( ! CreatePipe(&g_hChildStd_ERR_Rd, &g_hChildStd_ERR_Wr, &sa, 0) ) {
exit(1);
}
if ( ! SetHandleInformation(g_hChildStd_ERR_Rd, HANDLE_FLAG_INHERIT, 0) ){
exit(1);
}
if ( ! CreatePipe(&g_hChildStd_OUT_Rd, &g_hChildStd_OUT_Wr, &sa, 0) ) {
exit(1);
}
if ( ! SetHandleInformation(g_hChildStd_OUT_Rd, HANDLE_FLAG_INHERIT, 0) ){
exit(1);
}
char *szCmdline=command;
PROCESS_INFORMATION piProcInfo;
STARTUPINFO siStartInfo;
bool bSuccess = FALSE;
ZeroMemory( &piProcInfo, sizeof(PROCESS_INFORMATION) );
ZeroMemory( &siStartInfo, sizeof(STARTUPINFO) );
siStartInfo.cb = sizeof(STARTUPINFO);
siStartInfo.hStdError = g_hChildStd_ERR_Wr;
siStartInfo.hStdOutput = g_hChildStd_OUT_Wr;
siStartInfo.dwFlags |= STARTF_USESTDHANDLES;
bSuccess = CreateProcess(NULL,
szCmdline, // command line
NULL, // process security attributes
NULL, // primary thread security attributes
TRUE, // handles are inherited
CREATE_NO_WINDOW, // creation flags
NULL, // use parent's environment
NULL, // use parent's current directory
&siStartInfo, // STARTUPINFO pointer
&piProcInfo); // receives PROCESS_INFORMATION
CloseHandle(g_hChildStd_ERR_Wr);
CloseHandle(g_hChildStd_OUT_Wr);
if ( ! bSuccess ) {
exit(1);
}
DWORD dwRead;
CHAR chBuf[BUFSIZE];
bool bSuccess2 = FALSE;
std::string out = "", err = "";
for (;;) {
bSuccess2=ReadFile( g_hChildStd_OUT_Rd, chBuf, BUFSIZE, &dwRead, NULL);
if( ! bSuccess2 || dwRead == 0 ) break;
std::string s(chBuf, dwRead);
out += s;
}
dwRead = 0;
for (;;) {
bSuccess2=ReadFile( g_hChildStd_ERR_Rd, chBuf, BUFSIZE, &dwRead, NULL);
if( ! bSuccess2 || dwRead == 0 ) break;
std::string s(chBuf, dwRead);
err += s;
}
return out;
}
I tried several things but did not succeed in making it working.
Any help is appreciated!

Answer 1

The output of a command is a byte stream. So you read it as a byte stream. It's up to the two programs to agree on the encoding to use.
For example:
If you execute a .NET (C#/VB.NET) console application, the application can use the Console.OutputEncoding, to set the encoding the Console.Write[Line] method will use.
Console.OutputEncoding = Text.Encoding.UTF8;
Similarly, a PowerShell script can use the [Console]::OutputEncoding, to set the encoding the Write-Output or Write-Host cmdlets will use.
[Console]::OutputEncoding = [Text.Encoding]::UTF8
The cmd.exe or a batch file can use the chcp command.
chcp 65001
A Win32 application can use the SetConsoleOutputCP function to sets its output encoding, if it is using the WriteConsole. If the application is using the WriteFile, it just need to write the bytes encoded as desired already (e.g. using the WideCharToMultiByte).
SetConsoleOutputCP(CP_UTF8);
When you then read the application output, you decode the byte stream using the agreed encoding. E.g. using the MultiByteToWideChar function.