sdl

FORK: Simple Directmedia Layer
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SDL_poll.c (2348B)

      1 /*
      2   Simple DirectMedia Layer
      3   Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>
      4 
      5   This software is provided 'as-is', without any express or implied
      6   warranty.  In no event will the authors be held liable for any damages
      7   arising from the use of this software.
      8 
      9   Permission is granted to anyone to use this software for any purpose,
     10   including commercial applications, and to alter it and redistribute it
     11   freely, subject to the following restrictions:
     12 
     13   1. The origin of this software must not be misrepresented; you must not
     14      claim that you wrote the original software. If you use this software
     15      in a product, an acknowledgment in the product documentation would be
     16      appreciated but is not required.
     17   2. Altered source versions must be plainly marked as such, and must not be
     18      misrepresented as being the original software.
     19   3. This notice may not be removed or altered from any source distribution.
     20 */
     21 
     22 #include "../../SDL_internal.h"
     23 
     24 #include "SDL_poll.h"
     25 
     26 #ifdef HAVE_POLL
     27 #include <poll.h>
     28 #else
     29 #include <sys/time.h>
     30 #include <sys/types.h>
     31 #include <unistd.h>
     32 #endif
     33 #include <errno.h>
     34 
     35 
     36 int
     37 SDL_IOReady(int fd, SDL_bool forWrite, int timeoutMS)
     38 {
     39     int result;
     40 
     41     /* Note: We don't bother to account for elapsed time if we get EINTR */
     42     do
     43     {
     44 #ifdef HAVE_POLL
     45         struct pollfd info;
     46 
     47         info.fd = fd;
     48         if (forWrite) {
     49             info.events = POLLOUT;
     50         } else {
     51             info.events = POLLIN | POLLPRI;
     52         }
     53         result = poll(&info, 1, timeoutMS);
     54 #else
     55         fd_set rfdset, *rfdp = NULL;
     56         fd_set wfdset, *wfdp = NULL;
     57         struct timeval tv, *tvp = NULL;
     58 
     59         /* If this assert triggers we'll corrupt memory here */
     60         SDL_assert(fd >= 0 && fd < FD_SETSIZE);
     61 
     62         if (forWrite) {
     63             FD_ZERO(&wfdset);
     64             FD_SET(fd, &wfdset);
     65             wfdp = &wfdset;
     66         } else {
     67             FD_ZERO(&rfdset);
     68             FD_SET(fd, &rfdset);
     69             rfdp = &rfdset;
     70         }
     71 
     72         if (timeoutMS >= 0) {
     73             tv.tv_sec = timeoutMS / 1000;
     74             tv.tv_usec = (timeoutMS % 1000) * 1000;
     75             tvp = &tv;
     76         }
     77 
     78         result = select(fd + 1, rfdp, wfdp, NULL, tvp);
     79 #endif /* HAVE_POLL */
     80 
     81     } while ( result < 0 && errno == EINTR );
     82 
     83     return result;
     84 }
     85 
     86 /* vi: set ts=4 sw=4 expandtab: */