How to make thread sleep less than a millisecond on Windows
c++, sleep, winapi, windows
Solution
On Windows the use of `select` forces you to include the Winsock library which has to be initialized like this in your application:
WORD wVersionRequested = MAKEWORD(1,0);
WSADATA wsaData;
WSAStartup(wVersionRequested, &wsaData);
And then the select won't allow you to be called without any socket so you have to do a little more to create a microsleep method:
int usleep(long usec)
{
struct timeval tv;
fd_set dummy;
SOCKET s = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
FD_ZERO(&dummy);
FD_SET(s, &dummy);
tv.tv_sec = usec/1000000L;
tv.tv_usec = usec%1000000L;
return select(0, 0, 0, &dummy, &tv);
}
All these created usleep methods return zero when successful and non-zero for errors.
Problem
On Windows I have a problem I never encountered on Unix. That is how to get a thread to sleep for less than one millisecond. On Unix you typically have a number of choices (sleep, usleep and nanosleep) to fit your needs. On Windows, however, there is only Sleep with millisecond granularity. On Unix, I can use the use the `select` system call to create a microsecond sleep which is pretty straightforward: ``` int usleep(long usec) { struct timeval tv; tv.tv_sec = usec/1000000L; tv.tv_usec = usec%1000000L; return select(0, 0, 0, 0, &tv); } ``` How can I achieve the same on Windows?