libc/src/unistd/linux/pwrite.cpp

   1 //===-- Linux implementation of pwrite ------------------------------------===//
   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/unistd/pwrite.h"
  10
  11 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
  12 #include "src/__support/common.h"
  13
  14 #include "src/errno/libc_errno.h"
  15 #include <stdint.h>      // For uint64_t.
  16 #include <sys/syscall.h> // For syscall numbers.
  17
  18 namespace LIBC_NAMESPACE {
  19
  20 LLVM_LIBC_FUNCTION(ssize_t, pwrite,
  21                    (int fd, const void *buf, size_t count, off_t offset)) {
  22 #ifdef LIBC_TARGET_ARCH_IS_RISCV32
  23   static_assert(sizeof(off_t) == 8);
  24   ssize_t ret = LIBC_NAMESPACE::syscall_impl<ssize_t>(
  25       SYS_pwrite64, fd, buf, count, (long)offset,
  26       (long)(((uint64_t)(offset)) >> 32));
  27 #else
  28   ssize_t ret = LIBC_NAMESPACE::syscall_impl<ssize_t>(SYS_pwrite64, fd, buf,
  29                                                       count, offset);
  30 #endif
  31   if (ret < 0) {
  32     libc_errno = static_cast<int>(-ret);
  33     return -1;
  34   }
  35   return ret;
  36 }
  37
  38 } // namespace LIBC_NAMESPACE