// routines to use it (p blocks, cond p does not)
// 1 on success, -1 fail
int vrpn_Semaphore::p()
{
#ifdef sgi
if (fUsingLock) {
if (ussetlock(l) != 1) {
perror("vrpn_Semaphore::p: ussetlock:");
return -1;
}
}
else {
if (uspsema(ps) != 1) {
perror("vrpn_Semaphore::p: uspsema:");
return -1;
}
}
#elif defined(_WIN32)
switch (WaitForSingleObject(hSemaphore, INFINITE)) {
case WAIT_OBJECT_0:
// got the resource
break;
case WAIT_TIMEOUT:
ALL_ASSERT(0, "vrpn_Semaphore::p: infinite wait time timed out!");
return -1;
break;
case WAIT_ABANDONED:
ALL_ASSERT(0, "vrpn_Semaphore::p: thread holding resource died");
return -1;
break;
case WAIT_FAILED:
// get error info from windows (from FormatMessage help page)
LPVOID lpMsgBuf;
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM, NULL,
GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
// Default language
(LPTSTR)&lpMsgBuf, 0, NULL);
fprintf(stderr,
"vrpn_Semaphore::p: error waiting for resource, "
"WIN32 WaitForSingleObject call caused the following error: %s",
(LPTSTR)lpMsgBuf);
// Free the buffer.
LocalFree(lpMsgBuf);
return -1;
break;
default:
ALL_ASSERT(0, "vrpn_Semaphore::p: unknown return code");
return -1;
}
#else
// Posix by default
if (sem_wait(semaphore) != 0) {
perror("vrpn_Semaphore::p: ");
return -1;
}
#endif
return 1;
}
void accept_mutex_on()
{
switch(ussetlock(uslock)) {
case 1:
/* got lock */
break;
case 0:
fprintf(stderr, "didn't get lock\n");
exit(-1);
case -1:
perror("ussetlock");
exit(-1);
}
}
