[PATCH] libstdc++: implement formatter for std::filesystem::path
Ivan Lazaric
ivan.lazaric1@gmail.com
Fri Feb 13 22:16:13 GMT 2026
Changes performed to patch:
Switched to using __glibcxx_format_path in fs_path.h
Inlined __formatter_fs_path and removed
Applied suggestions for faster formatting via string_view
Generalized tests
Updated commit message
In tests, I am unsure how now test_format_invalid() can be generalized to Linux,
this is a pretty UTF-16/Windows specific test with a lone surrogate.
For example, path(L"\xd800") throws on Linux.
Also, is the condition path::value_type == wchar_t on it sufficient?
Should I add sizeof(wchar_t) == 2?
Updated patch follows:
>From 4abf58cdf530411e37a8e05d0d10e45f7c8d6466 Mon Sep 17 00:00:00 2001
From: Ivan Lazaric <ivan.lazaric1@gmail.com>
Date: Mon, 9 Feb 2026 13:26:36 +0100
Subject: [PATCH] libstdc++: implement formatter for std::filesystem::path
This patch implements formatting for std::filesystem::path from P2845R8,
and defines the feature test macro __cpp_lib_format_path to 202403L,
provided only in <filesystem>.
Formatting options are performed (if applicable) in order:
'g', '?', transcoding, fill-and-align & width
The standard specifies transcoding behaviour only when literal encoding
is UTF-8, leaving all other cases implementation defined.
Current implementation of filesystem::path assumes:
* char encoding is UTF-8
* wchar_t encoding is either UTF-32 or UTF-16
libstdc++-v3/ChangeLog:
* include/bits/fs_path.h: Include bits/formatfwd.h.
(formatter<filesystem::path, _CharT>): Define.
* include/bits/version.def: Add format_path.
* include/bits/version.h: Regenerate.
* include/std/filesystem: Expose __cpp_lib_format_path.
* testsuite/std/format/fs_path.cc: New test.
Signed-off-by: Ivan Lazaric <ivan.lazaric1@gmail.com>
Co-authored-by: Jonathan Wakely <jwakely@redhat.com>
---
libstdc++-v3/include/bits/fs_path.h | 108 ++++++++++++++++
libstdc++-v3/include/bits/version.def | 10 ++
libstdc++-v3/include/bits/version.h | 10 ++
libstdc++-v3/include/std/filesystem | 1 +
libstdc++-v3/testsuite/std/format/fs_path.cc | 124 +++++++++++++++++++
5 files changed, 253 insertions(+)
create mode 100644 libstdc++-v3/testsuite/std/format/fs_path.cc
diff --git a/libstdc++-v3/include/bits/fs_path.h
b/libstdc++-v3/include/bits/fs_path.h
index 07b74de6cbe..cb9e0778a21 100644
--- a/libstdc++-v3/include/bits/fs_path.h
+++ b/libstdc++-v3/include/bits/fs_path.h
@@ -50,6 +50,10 @@
# include <compare>
#endif
+#ifdef __glibcxx_format_path // C++ >= 26 && HOSTED
+# include <bits/formatfwd.h>
+#endif
+
#if defined(_WIN32) && !defined(__CYGWIN__)
# define _GLIBCXX_FILESYSTEM_IS_WINDOWS 1
#endif
@@ -1451,6 +1455,110 @@ template<>
{ return filesystem::hash_value(__p); }
};
+#ifdef __glibcxx_format_path // C++ >= 26 && HOSTED
+ template<__format::__char _CharT>
+ struct formatter<filesystem::path, _CharT>
+ {
+ formatter() = default;
+
+ [[__gnu__::__always_inline__]]
+ constexpr typename basic_format_parse_context<_CharT>::iterator
+ parse(basic_format_parse_context<_CharT>& __pc)
+ {
+ auto __first = __pc.begin();
+ const auto __last = __pc.end();
+ __format::_Spec<_CharT> __spec{};
+
+ auto __finalize = [this, &__spec] {
+ _M_spec = __spec;
+ };
+
+ auto __finished = [&] {
+ if (__first == __last || *__first == '}')
+ {
+ __finalize();
+ return true;
+ }
+ return false;
+ };
+
+ if (__finished())
+ return __first;
+
+ __first = __spec._M_parse_fill_and_align(__first, __last);
+ if (__finished())
+ return __first;
+
+ __first = __spec._M_parse_width(__first, __last, __pc);
+ if (__finished())
+ return __first;
+
+ if (*__first == '?')
+ {
+ __spec._M_debug = true;
+ ++__first;
+ }
+ if (__finished())
+ return __first;
+
+ if (*__first == 'g')
+ {
+ __spec._M_type = __format::_Pres_g;
+ ++__first;
+ }
+ if (__finished())
+ return __first;
+
+ __format::__failed_to_parse_format_spec();
+ }
+
+ template<typename _Out>
+ typename basic_format_context<_Out, _CharT>::iterator
+ format(const filesystem::path& __p,
+ basic_format_context<_Out, _CharT>& __fc) const
+ {
+ using _ValueT = filesystem::path::value_type;
+ using _FmtStrT = __format::__formatter_str<_CharT>;
+
+ filesystem::path::string_type __s;
+ basic_string_view<_ValueT> __sv;
+ if (_M_spec._M_type == __format::_Pres_g)
+ __sv = __s = __p.generic_string<_ValueT>();
+ else
+ __sv = __p.native();
+
+ auto __spec = _M_spec;
+ // 'g' should not be passed along.
+ __spec._M_type = __format::_Pres_none;
+
+ if constexpr (is_same_v<_CharT, _ValueT>)
+ return _FmtStrT(__spec).format(__sv, __fc);
+ else
+ {
+ __format::_Str_sink<_ValueT> __sink;
+ if (__spec._M_debug)
+ {
+ using __format::_Term_quote;
+ __format::__write_escaped(__sink.out(), __sv, _Term_quote);
+ __sv = __sink.view();
+ __spec._M_debug = 0;
+ }
+ basic_string<_CharT> __out_str;
+ using _View = basic_string_view<_ValueT>;
+ __out_str.assign_range(__unicode::_Utf_view<_CharT, _View>(__sv));
+ return _FmtStrT(__spec).format(__out_str, __fc);
+ }
+ }
+
+ constexpr void
+ set_debug_format() noexcept
+ { _M_spec._M_debug = true; }
+
+ private:
+ __format::_Spec<_CharT> _M_spec{};
+ };
+#endif // __glibcxx_format_path
+
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
diff --git a/libstdc++-v3/include/bits/version.def
b/libstdc++-v3/include/bits/version.def
index 4b8e9d43ec2..c7709ba3a07 100644
--- a/libstdc++-v3/include/bits/version.def
+++ b/libstdc++-v3/include/bits/version.def
@@ -1561,6 +1561,16 @@ ftms = {
};
};
+ftms = {
+ name = format_path;
+ // 202403 P2845R8 Formatting of std::filesystem::path
+ values = {
+ v = 202403;
+ cxxmin = 26;
+ hosted = yes;
+ };
+};
+
ftms = {
name = freestanding_algorithm;
values = {
diff --git a/libstdc++-v3/include/bits/version.h
b/libstdc++-v3/include/bits/version.h
index 7602225cb6d..c72cda506f1 100644
--- a/libstdc++-v3/include/bits/version.h
+++ b/libstdc++-v3/include/bits/version.h
@@ -1721,6 +1721,16 @@
#endif /* !defined(__cpp_lib_format_ranges) */
#undef __glibcxx_want_format_ranges
+#if !defined(__cpp_lib_format_path)
+# if (__cplusplus > 202302L) && _GLIBCXX_HOSTED
+# define __glibcxx_format_path 202403L
+# if defined(__glibcxx_want_all) || defined(__glibcxx_want_format_path)
+# define __cpp_lib_format_path 202403L
+# endif
+# endif
+#endif /* !defined(__cpp_lib_format_path) */
+#undef __glibcxx_want_format_path
+
#if !defined(__cpp_lib_freestanding_algorithm)
# if (__cplusplus >= 202100L)
# define __glibcxx_freestanding_algorithm 202311L
diff --git a/libstdc++-v3/include/std/filesystem
b/libstdc++-v3/include/std/filesystem
index f902c6feb77..b9900f49c33 100644
--- a/libstdc++-v3/include/std/filesystem
+++ b/libstdc++-v3/include/std/filesystem
@@ -37,6 +37,7 @@
#include <bits/requires_hosted.h>
#define __glibcxx_want_filesystem
+#define __glibcxx_want_format_path
#include <bits/version.h>
#ifdef __cpp_lib_filesystem // C++ >= 17 && HOSTED
diff --git a/libstdc++-v3/testsuite/std/format/fs_path.cc
b/libstdc++-v3/testsuite/std/format/fs_path.cc
new file mode 100644
index 00000000000..04ff4ac9be8
--- /dev/null
+++ b/libstdc++-v3/testsuite/std/format/fs_path.cc
@@ -0,0 +1,124 @@
+// { dg-do run { target c++26 } }
+// { dg-options "-fexec-charset=UTF-8" }
+
+#include <filesystem>
+#include <format>
+#include <testsuite_hooks.h>
+
+using std::filesystem::path;
+
+template<typename... Args>
+bool
+is_format_string_for(const char* str, Args&&... args)
+{
+ try {
+ (void) std::vformat(str, std::make_format_args(args...));
+ return true;
+ } catch (const std::format_error&) {
+ return false;
+ }
+}
+
+template<typename... Args>
+bool
+is_format_string_for(const wchar_t* str, Args&&... args)
+{
+ try {
+ (void) std::vformat(str, std::make_wformat_args(args...));
+ return true;
+ } catch (const std::format_error&) {
+ return false;
+ }
+}
+
+void
+test_format_spec()
+{
+ // [fs.path.fmtr.funcs]
+ // \nontermdef{path-format-spec}\br
+ // \opt{fill-and-align} \opt{width} \opt{\terminal{?}} \opt{\terminal{g}}
+ path p;
+ VERIFY( is_format_string_for("{}", p) );
+ VERIFY( is_format_string_for("{:}", p) );
+ VERIFY( is_format_string_for("{:?}", p) );
+ VERIFY( is_format_string_for("{:g}", p) );
+ VERIFY( is_format_string_for("{:?g}", p) );
+ VERIFY( is_format_string_for("{:?g}", p) );
+ VERIFY( is_format_string_for("{:F^32?g}", p) );
+ VERIFY( is_format_string_for("{:G<{}?g}", p, 32) );
+ VERIFY( is_format_string_for(L"{:G<{}?g}", p, 32) );
+
+ VERIFY( ! is_format_string_for("{:g?}", p) );
+}
+
+#define WIDEN_(C, S) ::std::__format::_Widen<C>(S, L##S)
+#define WFMT(S) WIDEN_(_FCharT, S)
+#define WPATH(S) WIDEN_(_PCharT, S)
+
+template<typename _FCharT, typename _PCharT>
+void
+test_format()
+{
+ std::basic_string<_FCharT> res;
+ res = std::format(WFMT("{}"), path(WPATH("/usr/include")));
+ VERIFY( res == WFMT("/usr/include") );
+ res = std::format(WFMT("{:.<10}"), path(WPATH("foo/bar")));
+ VERIFY( res == WFMT("foo/bar...") );
+ res = std::format(WFMT("{}"), path(WPATH("foo///bar")));
+ VERIFY( res == WFMT("foo///bar") );
+ res = std::format(WFMT("{:g}"), path(WPATH("foo///bar")));
+ VERIFY( res == WFMT("foo/bar") );
+ res = std::format(WFMT("{}"), path(WPATH("/path/with/new\nline")));
+ VERIFY( res == WFMT("/path/with/new\nline") );
+ res = std::format(WFMT("{:?}"), path(WPATH("multi\nline")));
+ VERIFY( res == WFMT("\"multi\\nline\"") );
+ res = std::format(WFMT("{:?g}"), path(WPATH("mu///lti\nli///ne")));
+ VERIFY( res == WFMT("\"mu/lti\\nli/ne\"") );
+ res = std::format(WFMT("{}"),
path(WPATH("\u0428\u0447\u0443\u0447\u044B\u043D\u0448\u0447\u044B\u043D\u0430")));
+ VERIFY( res ==
WFMT("\u0428\u0447\u0443\u0447\u044B\u043D\u0448\u0447\u044B\u043D\u0430")
);
+
+ if constexpr (path::preferred_separator == L'\\')
+ {
+ res = std::format(WFMT("{}"), path(WPATH("C:\\foo\\bar")));
+ VERIFY( res == WFMT("C:\\foo\\bar") );
+ res = std::format(WFMT("{:g}"), path(WPATH("C:\\foo\\bar")));
+ VERIFY( res == WFMT("C:/foo/bar") );
+ }
+}
+
+void
+test_format_invalid()
+{
+ if constexpr (std::is_same_v<path::value_type, wchar_t>)
+ {
+ std::string res;
+
+ path p(L"\xd800");
+ res = std::format("{}", p);
+ VERIFY( res == "\uFFFD" );
+ res = std::format("{:?}", p);
+ VERIFY( res == "\"\\x{d800}\"" );
+
+ path p2(L"///\xd800");
+ res = std::format("{}", p2);
+ VERIFY( res == "///\uFFFD" );
+ res = std::format("{:g}", p2);
+ VERIFY( res == "/\uFFFD" );
+ res = std::format("{:?}", p2);
+ VERIFY( res == "\"///\\x{d800}\"" );
+ res = std::format("{:?g}", p2);
+ VERIFY( res == "\"/\\x{d800}\"" );
+ res = std::format("{:C>14?g}", p2);
+ VERIFY( res == "CCC\"/\\x{d800}\"" );
+ }
+}
+
+int main()
+{
+ test_format_spec();
+ test_format<char, char>();
+ test_format<char, wchar_t>();
+ test_format<wchar_t, char>();
+ test_format<wchar_t, wchar_t>();
+ test_format_invalid();
+}
--
2.43.0
On Thu, Feb 12, 2026 at 1:31 PM Jonathan Wakely <jwakely@redhat.com> wrote:
>
> On Wed, 11 Feb 2026 at 13:56, Ivan Lazaric <ivan.lazaric1@gmail.com> wrote:
> >
> > This patch implements formatting for std::filesystem::path from P2845R8,
> > and defines the feature test macro __cpp_lib_format_path to 202403L,
> > provided only in <filesystem>.
> >
> > libstdc++-v3/ChangeLog:
> > * include/bits/fs_path.h: Include bits/formatfwd.h.
> > (__format::__formatter_fs_path<_CharT>)
> > (formatter<filesystem::path, _CharT>): Define.
> > * include/bits/version.def: Add format_path.
> > * include/bits/version.h: Regenerate.
> > * include/std/filesystem: Expose __cpp_lib_format_path.
> > * testsuite/std/format/fs_path.cc: New test.
> >
> > Signed-off-by: Ivan Lazaric <ivan.lazaric1@gmail.com>
> > Co-authored-by: Jonathan Wakely <jwakely@redhat.com>
> > ---
> > libstdc++-v3/include/bits/fs_path.h | 136 +++++++++++++++++++
> > libstdc++-v3/include/bits/version.def | 10 ++
> > libstdc++-v3/include/bits/version.h | 10 ++
> > libstdc++-v3/include/std/filesystem | 1 +
> > libstdc++-v3/testsuite/std/format/fs_path.cc | 88 ++++++++++++
> > 5 files changed, 245 insertions(+)
> > create mode 100644 libstdc++-v3/testsuite/std/format/fs_path.cc
> >
> > diff --git a/libstdc++-v3/include/bits/fs_path.h
> > b/libstdc++-v3/include/bits/fs_path.h
> > index 07b74de6cbe..1ca4942235e 100644
> > --- a/libstdc++-v3/include/bits/fs_path.h
> > +++ b/libstdc++-v3/include/bits/fs_path.h
> > @@ -50,6 +50,10 @@
> > # include <compare>
> > #endif
> >
> > +#ifdef __cpp_lib_format_path // C++ >= 26 && HOSTED
>
> I should have noticed this earlier, but this should really be testing
> __glibcxx_format_path instead.
>
> In this case it doesn't matter, because fs_path.h is only included by
> <filesystem> which defines __cpp_lib_format_path. But if we included
> fs_path.h elsewhere in the library without the rest of <filesystem>
> then __cpp_lib_format_path would not be defined, whereas
> __glibcxx_format_path would be.
>
> tl;dr most internal uses of feature test macros should use
> __glibcxx_xxx rather than __cpp_lib_xxx.
>
>
>
>
> > +# include <bits/formatfwd.h>
> > +#endif
> > +
> > #if defined(_WIN32) && !defined(__CYGWIN__)
> > # define _GLIBCXX_FILESYSTEM_IS_WINDOWS 1
> > #endif
> > @@ -1451,6 +1455,138 @@ template<>
> > { return filesystem::hash_value(__p); }
> > };
> >
> > +#ifdef __cpp_lib_format_path // C++ >= 26 && HOSTED
> > +namespace __format
> > +{
> > + template<__char _CharT>
> > + struct __formatter_fs_path
> > + {
> > + __formatter_fs_path() = default;
> > +
> > + constexpr
> > + __formatter_fs_path(_Spec<_CharT> __spec) noexcept
> > + : _M_spec(__spec)
> > + { }
> > +
> > + constexpr typename basic_format_parse_context<_CharT>::iterator
> > + parse(basic_format_parse_context<_CharT>& __pc)
> > + {
> > + auto __first = __pc.begin();
> > + const auto __last = __pc.end();
> > + _Spec<_CharT> __spec{};
> > +
> > + auto __finalize = [this, &__spec] {
> > + _M_spec = __spec;
> > + };
> > +
> > + auto __finished = [&] {
> > + if (__first == __last || *__first == '}')
> > + {
> > + __finalize();
> > + return true;
> > + }
> > + return false;
> > + };
> > +
> > + if (__finished())
> > + return __first;
> > +
> > + __first = __spec._M_parse_fill_and_align(__first, __last);
> > + if (__finished())
> > + return __first;
> > +
> > + __first = __spec._M_parse_width(__first, __last, __pc);
> > + if (__finished())
> > + return __first;
> > +
> > + if (*__first == '?')
> > + {
> > + __spec._M_debug = true;
> > + ++__first;
> > + }
> > + if (__finished())
> > + return __first;
> > +
> > + if (*__first == 'g')
> > + {
> > + __spec._M_type = _Pres_g;
> > + ++__first;
> > + }
> > + if (__finished())
> > + return __first;
> > +
> > + __format::__failed_to_parse_format_spec();
> > + }
> > +
> > + template<typename _Out>
> > + _Out
> > + format(const filesystem::path& __p,
> > + basic_format_context<_Out, _CharT>& __fc) const
> > + {
> > + using _ValueT = filesystem::path::value_type;
> > + using _FmtStrT = __formatter_str<_CharT>;
> > +
> > + filesystem::path::string_type __s;
> > + if (_M_spec._M_type == _Pres_g)
> > + __s = __p.generic_string<_ValueT>();
> > + else
> > + __s = __p.native();
> > +
> > + auto __spec = _M_spec;
> > + // 'g' should not be passed along.
> > + __spec._M_type = _Pres_none;
> > +
> > + if constexpr (is_same_v<_CharT, _ValueT>)
> > + return _FmtStrT(__spec).format(__s, __fc);
> > + else
> > + {
> > + if (__spec._M_debug)
> > + {
> > + _Str_sink<_ValueT> __sink;
> > + basic_string_view<_ValueT> __sv(__s);
> > + __format::__write_escaped(__sink.out(), __sv, _Term_quote);
> > + __s = std::move(__sink).get();
> > + __spec._M_debug = 0;
> > + }
> > + basic_string<_CharT> __out_str;
> > + using _View = basic_string_view<_ValueT>;
> > + __out_str.assign_range(__unicode::_Utf_view<_CharT, _View>(__s));
> > + return _FmtStrT(__spec).format(__out_str, __fc);
> > + }
> > + }
> > +
> > + constexpr void
> > + set_debug_format() noexcept
> > + { _M_spec._M_debug = true; }
> > +
> > + private:
> > + _Spec<_CharT> _M_spec{};
> > + };
> > +} // namespace __format
> > +
> > + template<__format::__char _CharT>
> > + struct formatter<filesystem::path, _CharT>
> > + {
> > + formatter() = default;
> > +
> > + [[__gnu__::__always_inline__]]
> > + constexpr typename basic_format_parse_context<_CharT>::iterator
> > + parse(basic_format_parse_context<_CharT>& __pc)
> > + { return _M_f.parse(__pc); }
> > +
> > + template<typename _Out>
> > + typename basic_format_context<_Out, _CharT>::iterator
> > + format(const filesystem::path& __p,
> > + basic_format_context<_Out, _CharT>& __fc) const
> > + { return _M_f.format(__p, __fc); }
> > +
> > + constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
> > +
> > + private:
> > + __format::__formatter_fs_path<_CharT> _M_f;
> > + };
> > +#endif // __cpp_lib_format_path
> > +
> > _GLIBCXX_END_NAMESPACE_VERSION
> > } // namespace std
> >
> > diff --git a/libstdc++-v3/include/bits/version.def
> > b/libstdc++-v3/include/bits/version.def
> > index 4b8e9d43ec2..c7709ba3a07 100644
> > --- a/libstdc++-v3/include/bits/version.def
> > +++ b/libstdc++-v3/include/bits/version.def
> > @@ -1561,6 +1561,16 @@ ftms = {
> > };
> > };
> >
> > +ftms = {
> > + name = format_path;
> > + // 202403 P2845R8 Formatting of std::filesystem::path
> > + values = {
> > + v = 202403;
> > + cxxmin = 26;
> > + hosted = yes;
> > + };
> > +};
> > +
> > ftms = {
> > name = freestanding_algorithm;
> > values = {
> > diff --git a/libstdc++-v3/include/bits/version.h
> > b/libstdc++-v3/include/bits/version.h
> > index 7602225cb6d..c72cda506f1 100644
> > --- a/libstdc++-v3/include/bits/version.h
> > +++ b/libstdc++-v3/include/bits/version.h
> > @@ -1721,6 +1721,16 @@
> > #endif /* !defined(__cpp_lib_format_ranges) */
> > #undef __glibcxx_want_format_ranges
> >
> > +#if !defined(__cpp_lib_format_path)
> > +# if (__cplusplus > 202302L) && _GLIBCXX_HOSTED
> > +# define __glibcxx_format_path 202403L
> > +# if defined(__glibcxx_want_all) || defined(__glibcxx_want_format_path)
> > +# define __cpp_lib_format_path 202403L
> > +# endif
> > +# endif
> > +#endif /* !defined(__cpp_lib_format_path) */
> > +#undef __glibcxx_want_format_path
> > +
> > #if !defined(__cpp_lib_freestanding_algorithm)
> > # if (__cplusplus >= 202100L)
> > # define __glibcxx_freestanding_algorithm 202311L
> > diff --git a/libstdc++-v3/include/std/filesystem
> > b/libstdc++-v3/include/std/filesystem
> > index f902c6feb77..b9900f49c33 100644
> > --- a/libstdc++-v3/include/std/filesystem
> > +++ b/libstdc++-v3/include/std/filesystem
> > @@ -37,6 +37,7 @@
> > #include <bits/requires_hosted.h>
> >
> > #define __glibcxx_want_filesystem
> > +#define __glibcxx_want_format_path
> > #include <bits/version.h>
> >
> > #ifdef __cpp_lib_filesystem // C++ >= 17 && HOSTED
> > diff --git a/libstdc++-v3/testsuite/std/format/fs_path.cc
> > b/libstdc++-v3/testsuite/std/format/fs_path.cc
> > new file mode 100644
> > index 00000000000..5105e73f611
> > --- /dev/null
> > +++ b/libstdc++-v3/testsuite/std/format/fs_path.cc
> > @@ -0,0 +1,88 @@
> > +// { dg-do run { target c++26 } }
> > +
> > +#include <filesystem>
> > +#include <format>
> > +#include <testsuite_hooks.h>
> > +
> > +using std::filesystem::path;
> > +
> > +template<typename... Args>
> > +bool
> > +is_format_string_for(const char* str, Args&&... args)
> > +{
> > + try {
> > + (void) std::vformat(str, std::make_format_args(args...));
> > + return true;
> > + } catch (const std::format_error&) {
> > + return false;
> > + }
> > +}
> > +
> > +template<typename... Args>
> > +bool
> > +is_format_string_for(const wchar_t* str, Args&&... args)
> > +{
> > + try {
> > + (void) std::vformat(str, std::make_wformat_args(args...));
> > + return true;
> > + } catch (const std::format_error&) {
> > + return false;
> > + }
> > +}
> > +
> > +void
> > +test_format_spec()
> > +{
> > + // [fs.path.fmtr.funcs]
> > + // \nontermdef{path-format-spec}\br
> > + // \opt{fill-and-align} \opt{width} \opt{\terminal{?}} \opt{\terminal{g}}
> > + path p;
> > + VERIFY( is_format_string_for("{}", p) );
> > + VERIFY( is_format_string_for("{:}", p) );
> > + VERIFY( is_format_string_for("{:?}", p) );
> > + VERIFY( is_format_string_for("{:g}", p) );
> > + VERIFY( is_format_string_for("{:?g}", p) );
> > + VERIFY( is_format_string_for("{:?g}", p) );
> > + VERIFY( is_format_string_for("{:F^32?g}", p) );
> > + VERIFY( is_format_string_for("{:G<{}?g}", p, 32) );
> > + VERIFY( is_format_string_for(L"{:G<{}?g}", p, 32) );
> > +
> > + VERIFY( ! is_format_string_for("{:g?}", p) );
> > +}
> > +
> > +void
> > +test_format_path()
> > +{
> > + VERIFY( std::format("{}", path("/usr/include")) == "/usr/include" );
> > + VERIFY( std::format("{:.<10}", path("foo/bar")) == "foo/bar..." );
> > + VERIFY( std::format("{}", path("foo///bar")) == "foo///bar" );
> > + VERIFY( std::format("{:g}", path("foo///bar")) == "foo/bar" );
> > + VERIFY( std::format("{}", path("/path/with/new\nline")) ==
> > "/path/with/new\nline" );
> > + VERIFY( std::format("{:?}", path("multi\nline")) == "\"multi\\nline\"" );
> > + VERIFY( std::format("{:?g}", path("mu///lti\nli///ne")) ==
> > "\"mu/lti\\nli/ne\"" );
> > + VERIFY( std::format(L"{}",
> > path(L"\u0428\u0447\u0443\u0447\u044B\u043D\u0448\u0447\u044B\u043D\u0430"))
> > == L"\u0428\u0447\u0443\u0447\u044B\u043D\u0448\u0447\u044B\u043D\u0430"
> > );
> > +
> > + if constexpr (path::preferred_separator == L'\\')
> > + {
> > + VERIFY( std::format("{}", path("C:\\foo\\bar")) == "C:\\foo\\bar" );
> > + VERIFY( std::format("{:g}", path("C:\\foo\\bar")) == "C:/foo/bar" );
> > +
> > + path p(L"\xd800");
> > + VERIFY( std::format("{}", p) == "\uFFFD" );
> > + VERIFY( std::format("{:?}", p) == "\"\\x{d800}\"" );
> > + VERIFY( std::format(L"{:?}", p) == L"\"\\x{d800}\"" );
> > +
> > + path p2(L"///\xd800");
> > + VERIFY( std::format("{}", p2) == "///\uFFFD" );
> > + VERIFY( std::format("{:g}", p2) == "/\uFFFD" );
> > + VERIFY( std::format("{:?}", p2) == "\"///\\x{d800}\"" );
> > + VERIFY( std::format("{:?g}", p2) == "\"/\\x{d800}\"" );
> > + VERIFY( std::format("{:C>14?g}", p2) == "CCC\"/\\x{d800}\"" );
> > + }
> > +}
> > +
> > +int main()
> > +{
> > + test_format_spec();
> > + test_format_path();
> > +}
> > --
> > 2.43.0
> >
>
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