xref: /aosp_15_r20/external/llvm-libc/src/stdio/generic/ftell.cpp (revision 71db0c75aadcf003ffe3238005f61d7618a3fead)
1*71db0c75SAndroid Build Coastguard Worker //===-- Implementation of ftell -------------------------------------------===//
2*71db0c75SAndroid Build Coastguard Worker //
3*71db0c75SAndroid Build Coastguard Worker // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4*71db0c75SAndroid Build Coastguard Worker // See https://llvm.org/LICENSE.txt for license information.
5*71db0c75SAndroid Build Coastguard Worker // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6*71db0c75SAndroid Build Coastguard Worker //
7*71db0c75SAndroid Build Coastguard Worker //===----------------------------------------------------------------------===//
8*71db0c75SAndroid Build Coastguard Worker 
9*71db0c75SAndroid Build Coastguard Worker #include "src/stdio/ftell.h"
10*71db0c75SAndroid Build Coastguard Worker #include "src/__support/File/file.h"
11*71db0c75SAndroid Build Coastguard Worker 
12*71db0c75SAndroid Build Coastguard Worker #include "src/__support/macros/config.h"
13*71db0c75SAndroid Build Coastguard Worker #include "src/errno/libc_errno.h"
14*71db0c75SAndroid Build Coastguard Worker 
15*71db0c75SAndroid Build Coastguard Worker namespace LIBC_NAMESPACE_DECL {
16*71db0c75SAndroid Build Coastguard Worker 
17*71db0c75SAndroid Build Coastguard Worker LLVM_LIBC_FUNCTION(long, ftell, (::FILE * stream)) {
18*71db0c75SAndroid Build Coastguard Worker   auto result = reinterpret_cast<LIBC_NAMESPACE::File *>(stream)->tell();
19*71db0c75SAndroid Build Coastguard Worker   if (!result.has_value()) {
20*71db0c75SAndroid Build Coastguard Worker     libc_errno = result.error();
21*71db0c75SAndroid Build Coastguard Worker     return -1;
22*71db0c75SAndroid Build Coastguard Worker   }
23*71db0c75SAndroid Build Coastguard Worker   // tell() returns an off_t (64-bit signed integer), but this function returns
24*71db0c75SAndroid Build Coastguard Worker   // a long (32-bit signed integer in 32-bit systems). We add a cast here to
25*71db0c75SAndroid Build Coastguard Worker   // silence a "implicit conversion loses integer precision" warning when
26*71db0c75SAndroid Build Coastguard Worker   // compiling for 32-bit systems.
27*71db0c75SAndroid Build Coastguard Worker   return static_cast<long>(result.value());
28*71db0c75SAndroid Build Coastguard Worker }
29*71db0c75SAndroid Build Coastguard Worker 
30*71db0c75SAndroid Build Coastguard Worker } // namespace LIBC_NAMESPACE_DECL
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