SubProcess
struct SubProcess
{
CFile stdin_file;
CFile stdout_file;
CFile stderr_file;
Win32_HANDLE hProcess @if(env::WIN32);
Win32_HANDLE hStdInput @if(env::WIN32);
Win32_HANDLE hEventOutput @if(env::WIN32);
Win32_HANDLE hEventError @if(env::WIN32);
Pid_t child @if(!env::WIN32);
int return_status @if(!env::WIN32);
bool is_alive;
}