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-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "src/stdio/ftell.h" 10 #include "src/__support/File/file.h" 11 12 #include "src/__support/macros/config.h" 13 #include "src/errno/libc_errno.h" 14 15 namespace LIBC_NAMESPACE_DECL { 16 17 LLVM_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 returns 24 // a long (32-bit signed integer in 32-bit systems). We add a cast here to 25 // silence a "implicit conversion loses integer precision" warning when 26 // compiling for 32-bit systems. 27 return static_cast<long>(result.value()); 28 } 29 30 } // namespace LIBC_NAMESPACE_DECL 31