1//===-- Interactive unittests for select ----------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "src/sys/select/select.h"
10#include "src/unistd/read.h"
11#include "test/UnitTest/ErrnoCheckingTest.h"
12#include "test/UnitTest/ErrnoSetterMatcher.h"
13#include "test/UnitTest/Test.h"
14
15#include <sys/select.h>
16#include <unistd.h>
17
18using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
19using LlvmLibcSelectTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;
20
21// This test is not be run automatically as part of the libc testsuite.
22// Instead, one has to run it manually and press a key on the keyboard
23// to make the test succeed.
24TEST_F(LlvmLibcSelectTest, ReadStdinAfterSelect) {
25 constexpr int STDIN_FD = 0;
26 fd_set set;
27 FD_ZERO(&set);
28 FD_SET(STDIN_FD, &set);
29 struct timeval zero {
30 .tv_sec: 0, .tv_usec: 0
31 }; // No wait
32 struct timeval hr {
33 .tv_sec: 3600, .tv_usec: 0
34 }; // Wait for an hour.
35
36 // Zero timeout means we don't wait for input. So, select should return
37 // immediately.
38 ASSERT_THAT(
39 LIBC_NAMESPACE::select(STDIN_FD + 1, &set, nullptr, nullptr, &zero),
40 Succeeds(0));
41 // The set should indicate that stdin is NOT ready for reading.
42 ASSERT_EQ(0, FD_ISSET(STDIN_FD, &set));
43
44 FD_SET(STDIN_FD, &set);
45 // Wait for an hour and give the user a chance to hit a key.
46 ASSERT_THAT(LIBC_NAMESPACE::select(STDIN_FD + 1, &set, nullptr, nullptr, &hr),
47 Succeeds(1));
48 // The set should indicate that stdin is ready for reading.
49 ASSERT_EQ(1, FD_ISSET(STDIN_FD, &set));
50
51 // Verify that atleast one character can be read.
52 char c;
53 ASSERT_THAT(LIBC_NAMESPACE::read(STDIN_FD, &c, 1), Succeeds(ssize_t(1)));
54}
55

source code of libc/test/src/sys/select/select_ui_test.cpp