xref: /third_party/glfw/src/posix_poll.c (revision b877906b)
1//========================================================================
2// GLFW 3.5 POSIX - www.glfw.org
3//------------------------------------------------------------------------
4// Copyright (c) 2022 Camilla Löwy <elmindreda@glfw.org>
5//
6// This software is provided 'as-is', without any express or implied
7// warranty. In no event will the authors be held liable for any damages
8// arising from the use of this software.
9//
10// Permission is granted to anyone to use this software for any purpose,
11// including commercial applications, and to alter it and redistribute it
12// freely, subject to the following restrictions:
13//
14// 1. The origin of this software must not be misrepresented; you must not
15//    claim that you wrote the original software. If you use this software
16//    in a product, an acknowledgment in the product documentation would
17//    be appreciated but is not required.
18//
19// 2. Altered source versions must be plainly marked as such, and must not
20//    be misrepresented as being the original software.
21//
22// 3. This notice may not be removed or altered from any source
23//    distribution.
24//
25//========================================================================
26
27#if !defined(_GNU_SOURCE)
28#define _GNU_SOURCE
29#endif
30
31#include "internal.h"
32
33#if defined(GLFW_BUILD_POSIX_POLL)
34
35#include <signal.h>
36#include <time.h>
37#include <errno.h>
38
39GLFWbool _glfwPollPOSIX(struct pollfd* fds, nfds_t count, double* timeout)
40{
41    for (;;)
42    {
43        if (timeout)
44        {
45            const uint64_t base = _glfwPlatformGetTimerValue();
46
47#if defined(__linux__) || defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__CYGWIN__)
48            const time_t seconds = (time_t) *timeout;
49            const long nanoseconds = (long) ((*timeout - seconds) * 1e9);
50            const struct timespec ts = { seconds, nanoseconds };
51            const int result = ppoll(fds, count, &ts, NULL);
52#elif defined(__NetBSD__)
53            const time_t seconds = (time_t) *timeout;
54            const long nanoseconds = (long) ((*timeout - seconds) * 1e9);
55            const struct timespec ts = { seconds, nanoseconds };
56            const int result = pollts(fds, count, &ts, NULL);
57#else
58            const int milliseconds = (int) (*timeout * 1e3);
59            const int result = poll(fds, count, milliseconds);
60#endif
61            const int error = errno; // clock_gettime may overwrite our error
62
63            *timeout -= (_glfwPlatformGetTimerValue() - base) /
64                (double) _glfwPlatformGetTimerFrequency();
65
66            if (result > 0)
67                return GLFW_TRUE;
68            else if (result == -1 && error != EINTR && error != EAGAIN)
69                return GLFW_FALSE;
70            else if (*timeout <= 0.0)
71                return GLFW_FALSE;
72        }
73        else
74        {
75            const int result = poll(fds, count, -1);
76            if (result > 0)
77                return GLFW_TRUE;
78            else if (result == -1 && errno != EINTR && errno != EAGAIN)
79                return GLFW_FALSE;
80        }
81    }
82}
83
84#endif // GLFW_BUILD_POSIX_POLL
85
86