[libc++] Move fpos into its own header

[philnik]

Summary

For some reason <string> defines std::fpos, which should be defined in <ios>.

[Mordante]

The test test/std/input.output/iostreams.base/fpos/fpos.operations/fpos.pass.cpp also needs to be updated

• Update the includes
• Update the synopsis

libcxx/include/__ios/fpos.h

30

Would be nice to use _LIBCPP_HIDE_FROM_ABI here.

57

Please remove one blank line.

[philnik]

• Address comments

[Mordante]

LGTM if the CI passes.

[• Quuxplusone]

libcxx/include/__ios/fpos.h

2

Since you're _LIBCPP_HIDE_FROM_ABI'ing this code already, do you also want to 2-space-indent it?

18

D118800 is related. Please use the prevailing style until/unless we agree to do something different:

$ git grep '#pragma GCC system_header' ../libcxx/include/ | wc -l
     484
$ git grep '# pragma GCC system_header' ../libcxx/include/ | wc -l
       1
$ git grep '#  pragma GCC system_header' ../libcxx/include/ | wc -l
      16
$ git grep '#   pragma GCC system_header' ../libcxx/include/ | wc -l
       2
$ git grep '#    pragma GCC system_header' ../libcxx/include/ | wc -l
       0

[philnik]

@Quuxplusone are you OK with it just being clang-formatted? I know you and I disagree what is readable, but I think in this case there is nothing you would object to.

libcxx/include/__ios/fpos.h

18

I'll go with 2 spaces here, since that seems to be what you do in D118800.

[• Quuxplusone]

Two nits, then ship it!

libcxx/include/__ios/fpos.h

71

Let's linebreak after _LIBCPP_HIDE_FROM_ABI and before bool, in each case.

77

[philnik]

• Address nits, generate files

libcxx/include/CMakeLists.txt

set(files
   __functional/ranges_operations.h
   __functional/reference_wrapper.h
   __functional/unary_function.h
   __functional/unary_negate.h
   __functional/unwrap_ref.h
   __functional/weak_result_type.h
   __functional_base
   __hash_table
+  __ios/fpos.h
   __iterator/access.h
   __iterator/advance.h
   __iterator/back_insert_iterator.h
   __iterator/common_iterator.h
   __iterator/concepts.h
   __iterator/counted_iterator.h
   __iterator/data.h
   __iterator/default_sentinel.h

libcxx/include/__ios/fpos.h

+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___IOS_FPOS_H
+#define _LIBCPP___IOS_FPOS_H
+
+#include <__config>
+#include <iosfwd>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _StateT>
+class _LIBCPP_TEMPLATE_VIS fpos {
+private:
+  _StateT __st_;
+  streamoff __off_;
+
+public:
+  _LIBCPP_HIDE_FROM_ABI fpos(streamoff __off = streamoff()) : __st_(), __off_(__off) {}
+
+  _LIBCPP_HIDE_FROM_ABI operator streamoff() const { return __off_; }
+
+  _LIBCPP_HIDE_FROM_ABI _StateT state() const { return __st_; }
+  _LIBCPP_HIDE_FROM_ABI void state(_StateT __st) { __st_ = __st; }
+
+  _LIBCPP_HIDE_FROM_ABI fpos& operator+=(streamoff __off) {
+    __off_ += __off;
+    return *this;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI fpos operator+(streamoff __off) const {
+    fpos __t(*this);
+    __t += __off;
+    return __t;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI fpos& operator-=(streamoff __off) {
+    __off_ -= __off;
+    return *this;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI fpos operator-(streamoff __off) const {
+    fpos __t(*this);
+    __t -= __off;
+    return __t;
+  }
+};
+
+template <class _StateT>
+inline _LIBCPP_HIDE_FROM_ABI
+streamoff operator-(const fpos<_StateT>& __x, const fpos<_StateT>& __y) {
+  return streamoff(__x) - streamoff(__y);
+}
+
+template <class _StateT>
+inline _LIBCPP_HIDE_FROM_ABI
+bool operator==(const fpos<_StateT>& __x, const fpos<_StateT>& __y) {
+  return streamoff(__x) == streamoff(__y);
+}
+
+template <class _StateT>
+inline _LIBCPP_HIDE_FROM_ABI
+bool operator!=(const fpos<_StateT>& __x, const fpos<_StateT>& __y) {
+  return streamoff(__x) != streamoff(__y);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___IOS_FPOS_H

libcxx/include/ios

 error_condition make_error_condition(io_errc e) noexcept;
 storage-class-specifier const error_category& iostream_category() noexcept;
 
 }  // std
 
 */
 
 #include <__config>
+#include <__ios/fpos.h>
 #include <__locale>
 #include <iosfwd>
 #include <system_error>
 #include <version>
 
 #if !defined(_LIBCPP_HAS_NO_ATOMIC_HEADER)
 #include <atomic>     // for __xindex_
 #endif

libcxx/include/module.modulemap

module std [system] {
   module iomanip {
     header "iomanip"
     export *
   }
   module ios {
     header "ios"
     export iosfwd
     export *
+
+    module __ios {
+      module fpos { private header "__ios/fpos.h" }
+    }
   }
   module iosfwd {
     header "iosfwd"
     export *
   }
   module iostream {
     header "iostream"
     export ios

libcxx/include/string

 
 }  // std
 
 */
 
 #include <__config>
 #include <__debug>
 #include <__functional_base>
+#include <__ios/fpos.h>
 #include <__iterator/wrap_iter.h>
 #include <algorithm>
 #include <compare>
 #include <cstdio>  // EOF
 #include <cstdlib>
 #include <cstring>
 #include <initializer_list>
 #include <iosfwd>
 #include <iterator>
 #include <memory>
 #include <stdexcept>
 #include <string_view>
 #include <type_traits>
 #include <utility>
 #include <version>
 
 #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
-#   include <cwchar>
+#  include <cwchar>
 #endif
 
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-# include <cstdint>
+#  include <cstdint>
 #endif
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_PUSH_MACROS
 #include <__undef_macros>
 
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-// fpos
-
-template <class _StateT>
-class _LIBCPP_TEMPLATE_VIS fpos
-{
-private:
-    _StateT __st_;
-    streamoff __off_;
-public:
-    _LIBCPP_INLINE_VISIBILITY fpos(streamoff __off = streamoff()) : __st_(), __off_(__off) {}
-
-    _LIBCPP_INLINE_VISIBILITY operator streamoff() const {return __off_;}
-
-    _LIBCPP_INLINE_VISIBILITY _StateT state() const {return __st_;}
-    _LIBCPP_INLINE_VISIBILITY void state(_StateT __st) {__st_ = __st;}
-
-    _LIBCPP_INLINE_VISIBILITY fpos& operator+=(streamoff __off) {__off_ += __off; return *this;}
-    _LIBCPP_INLINE_VISIBILITY fpos  operator+ (streamoff __off) const {fpos __t(*this); __t += __off; return __t;}
-    _LIBCPP_INLINE_VISIBILITY fpos& operator-=(streamoff __off) {__off_ -= __off; return *this;}
-    _LIBCPP_INLINE_VISIBILITY fpos  operator- (streamoff __off) const {fpos __t(*this); __t -= __off; return __t;}
-};
-
-template <class _StateT>
-inline _LIBCPP_INLINE_VISIBILITY
-streamoff operator-(const fpos<_StateT>& __x, const fpos<_StateT>& __y)
-    {return streamoff(__x) - streamoff(__y);}
-
-template <class _StateT>
-inline _LIBCPP_INLINE_VISIBILITY
-bool operator==(const fpos<_StateT>& __x, const fpos<_StateT>& __y)
-    {return streamoff(__x) == streamoff(__y);}
-
-template <class _StateT>
-inline _LIBCPP_INLINE_VISIBILITY
-bool operator!=(const fpos<_StateT>& __x, const fpos<_StateT>& __y)
-    {return streamoff(__x) != streamoff(__y);}
-
 // basic_string
 
 template<class _CharT, class _Traits, class _Allocator>
 basic_string<_CharT, _Traits, _Allocator>
 operator+(const basic_string<_CharT, _Traits, _Allocator>& __x,
           const basic_string<_CharT, _Traits, _Allocator>& __y);
 
 template<class _CharT, class _Traits, class _Allocator>

libcxx/test/libcxx/diagnostics/detail.headers/ios/fpos.module.verify.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: modules-build
+
+// WARNING: This test was generated by 'generate_private_header_tests.py'
+// and should not be edited manually.
+
+// expected-error@*:* {{use of private header from outside its module: '__ios/fpos.h'}}
+#include <__ios/fpos.h>

libcxx/test/std/input.output/iostreams.base/fpos/fpos.operations/fpos.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
-#include "test_macros.h"
+// <ios>
+
+// template <class stateT>
+// class fpos;
 
-#include <string>
 #include <cassert>
+#include <ios>
 #include <type_traits>
 
-// <string>
-
-// template <class stateT>
-// class fpos;
+#include "test_macros.h"
 
 template<class T, class = void>
 struct is_equality_comparable : std::false_type { };
 
 template<class T>
 struct is_equality_comparable
 <T, typename std::enable_if<true, decltype(std::declval<T const&>() == std::declval<T const&>(),
                                            (void)0)>::type