1//===---------- Linux implementation of the POSIX posix_madvise function --===//
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/mman/posix_madvise.h"
10
11#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
12#include "src/__support/common.h"
13#include "src/__support/macros/config.h"
14
15#include <sys/syscall.h> // For syscall numbers.
16
17namespace LIBC_NAMESPACE_DECL {
18
19// This function is currently linux only. It has to be refactored suitably if
20// posix_madvise is to be supported on non-linux operating systems also.
21LLVM_LIBC_FUNCTION(int, posix_madvise, (void *addr, size_t size, int advice)) {
22 // POSIX_MADV_DONTNEED does nothing because the default MADV_DONTNEED may
23 // cause data loss, which the posix madvise does not allow.
24 if (advice == POSIX_MADV_DONTNEED) {
25 return 0;
26 }
27 int ret = LIBC_NAMESPACE::syscall_impl<int>(
28 SYS_madvise, reinterpret_cast<long>(addr), size, advice);
29 return ret < 0 ? -ret : 0;
30}
31
32} // namespace LIBC_NAMESPACE_DECL
33

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source code of libc/src/sys/mman/linux/posix_madvise.cpp