SDL  2.0
SDL_poll.c
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1 /*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2017 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_assert.h"
25 #include "SDL_poll.h"
26 
27 #undef HAVE_POLL
28 #ifdef HAVE_POLL
29 #include <poll.h>
30 #else
31 #include <sys/time.h>
32 #include <sys/types.h>
33 #include <unistd.h>
34 #endif
35 #include <errno.h>
36 
37 
38 int
39 SDL_IOReady(int fd, SDL_bool forWrite, int timeoutMS)
40 {
41  int result;
42 
43  /* Note: We don't bother to account for elapsed time if we get EINTR */
44  do
45  {
46 #ifdef HAVE_POLL
47  struct pollfd info;
48 
49  info.fd = fd;
50  if (forWrite) {
51  info.events = POLLOUT;
52  } else {
53  info.events = POLLIN | POLLPRI;
54  }
55  result = poll(&info, 1, timeoutMS);
56 #else
57  fd_set rfdset, *rfdp = NULL;
58  fd_set wfdset, *wfdp = NULL;
59  struct timeval tv, *tvp = NULL;
60 
61  /* If this assert triggers we'll corrupt memory here */
62  SDL_assert(fd >= 0 && fd < FD_SETSIZE);
63 
64  if (forWrite) {
65  FD_ZERO(&wfdset);
66  FD_SET(fd, &wfdset);
67  wfdp = &wfdset;
68  } else {
69  FD_ZERO(&rfdset);
70  FD_SET(fd, &rfdset);
71  rfdp = &rfdset;
72  }
73 
74  if (timeoutMS >= 0) {
75  tv.tv_sec = timeoutMS / 1000;
76  tv.tv_usec = (timeoutMS % 1000) * 1000;
77  tvp = &tv;
78  }
79 
80  result = select(fd + 1, rfdp, wfdp, NULL, tvp);
81 #endif /* HAVE_POLL */
82 
83  } while ( result < 0 && errno == EINTR );
84 
85  return result;
86 }
87 
88 /* vi: set ts=4 sw=4 expandtab: */
int SDL_IOReady(int fd, SDL_bool forWrite, int timeoutMS)
Definition: SDL_poll.c:39
GLuint64EXT * result
#define SDL_assert(condition)
Definition: SDL_assert.h:169
#define NULL
Definition: begin_code.h:164
SDL_bool
Definition: SDL_stdinc.h:139
GLuint64 GLenum GLint fd
Definition: gl2ext.h:1508