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- /*
- * Copyright 2014-present Facebook, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- /**
- * Work around the lack of <sys/eventfd.h> on glibc 2.5.1 which we still
- * need to support, sigh.
- */
- #pragma once
- #ifndef FOLLY_NO_CONFIG
- #include <folly/folly-config.h>
- #endif
- #if __has_include(<features.h>)
- #include <features.h>
- #endif
- #if defined(__GLIBC__) && !defined(__APPLE__)
- #if __GLIBC_PREREQ(2, 9)
- #define FOLLY_GLIBC_2_9
- #endif
- #endif
- // <sys/eventfd.h> doesn't exist on older glibc versions
- #ifdef FOLLY_GLIBC_2_9
- #include <sys/eventfd.h>
- #else /* !def FOLLY_GLIBC_2_9 */
- #include <fcntl.h>
- #include <sys/syscall.h>
- #include <unistd.h>
- // Use existing __NR_eventfd2 if already defined
- // Values from the Linux kernel source:
- // arch/x86/include/asm/unistd_{32,64}.h
- #ifndef __NR_eventfd2
- #if FOLLY_X64
- /* nolint */
- #define __NR_eventfd2 290
- #elif defined(__i386__)
- /* nolint */
- #define __NR_eventfd2 328
- #else
- #error "Can't define __NR_eventfd2 for your architecture."
- #endif
- #endif
- enum {
- EFD_SEMAPHORE = 1,
- #define EFD_SEMAPHORE EFD_SEMAPHORE
- EFD_CLOEXEC = 02000000,
- #define EFD_CLOEXEC EFD_CLOEXEC
- EFD_NONBLOCK = 04000
- #define EFD_NONBLOCK EFD_NONBLOCK
- };
- // http://www.kernel.org/doc/man-pages/online/pages/man2/eventfd.2.html
- // Use the eventfd2 system call, as in glibc 2.9+
- // (requires kernel 2.6.30+)
- #define eventfd(initval, flags) syscall(__NR_eventfd2, (initval), (flags))
- #endif /* !(defined(__GLIBC__) && __GLIBC_PREREQ(2, 9)) */
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