31 lines · cpp
1//===-- Implementation of ftell -------------------------------------------===//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-exception6//7//===----------------------------------------------------------------------===//8 9#include "src/stdio/ftell.h"10#include "src/__support/File/file.h"11 12#include "src/__support/libc_errno.h"13#include "src/__support/macros/config.h"14 15namespace LIBC_NAMESPACE_DECL {16 17LLVM_LIBC_FUNCTION(long, ftell, (::FILE * stream)) {18 auto result = reinterpret_cast<LIBC_NAMESPACE::File *>(stream)->tell();19 if (!result.has_value()) {20 libc_errno = result.error();21 return -1;22 }23 // tell() returns an off_t (64-bit signed integer), but this function returns24 // a long (32-bit signed integer in 32-bit systems). We add a cast here to25 // silence a "implicit conversion loses integer precision" warning when26 // compiling for 32-bit systems.27 return static_cast<long>(result.value());28}29 30} // namespace LIBC_NAMESPACE_DECL31