如何获得 fmt::format 与wchar_t一起使用?

我想让 fmt：：format 从 EA 的 STL 返回一个字符串，但是当我尝试从文档中修改这段代码时——这工作正常：

// Prints formatted error message.
void
vreport_error(const char *format, fmt::format_args args) {
fmt::print("Error: ");
fmt::vprint(format, args);
}
template <typename... Args>
void
report_error(const char *format, const Args &... args) {
vreport_error(format, fmt::make_format_args(args...));
}

要使用 wchar_t 而不是 char：

// Prints formatted error message.
void vreport_error2(const wchar_t *format, fmt::format_args args);
template <typename... Args>
void
report_error2(const wchar_t *format, const Args &... args) {
vreport_error2(format, fmt::make_format_args(args...));
}

我得到：

2>fmtcore.h(1219,1): error C2665:  'fmt::v5::basic_format_args<fmt::v5::wformat_context>::basic_format_args': none of the 4 overloads could convert all the argument types
2>fmtcore.h(1219,1): error C2665:       : basic_format_args<wformat_context>(std::forward<Args>(args)...) {}
2>fmtcore.h(1219,1): error C2665: ^ (compiling source file ..coretypedefs.cpp)
2>fmtcore.h(1207,1): message :  could be 'fmt::v5::basic_format_args<fmt::v5::wformat_context>::basic_format_args(fmt::v5::basic_format_args<fmt::v5::wformat_context> &&)'
2>fmtcore.h(1207,1): message : };
2>fmtcore.h(1207,1): message : ^ (compiling source file ..coretypedefs.cpp)
2>fmtcore.h(1207,1): message :  or       'fmt::v5::basic_format_args<fmt::v5::wformat_context>::basic_format_args(const fmt::v5::basic_format_args<fmt::v5::wformat_context> &)'
2>fmtcore.h(1207,1): message : };
2>fmtcore.h(1207,1): message : ^ (compiling source file ..coretypedefs.cpp)
2>fmtcore.h(1189,3): message :  or       'fmt::v5::basic_format_args<fmt::v5::wformat_context>::basic_format_args(const fmt::v5::basic_format_arg<Context> *,int)'
2>fmtcore.h(1189,3): message :         with
2>fmtcore.h(1189,3): message :         [
2>fmtcore.h(1189,3): message :             Context=fmt::v5::wformat_context
2>fmtcore.h(1189,3): message :         ]
2>fmtcore.h(1189,3): message :   basic_format_args(const format_arg* args, int count)
2>fmtcore.h(1189,3): message :   ^ (compiling source file ..coretypedefs.cpp)
2>fmtcore.h(1171,3): message :  or       'fmt::v5::basic_format_args<fmt::v5::wformat_context>::basic_format_args(void)'
2>fmtcore.h(1171,3): message :   basic_format_args() : types_(0) {}
2>fmtcore.h(1171,3): message :   ^ (compiling source file ..coretypedefs.cpp)
2>fmtcore.h(1219,1): message :  while trying to match the argument list '(fmt::v5::format_args)'
2>fmtcore.h(1219,1): message :       : basic_format_args<wformat_context>(std::forward<Args>(args)...) {}
2>fmtcore.h(1219,1): message : ^ (compiling source file ..coretypedefs.cpp)

或者，如果我尝试转换为 char 然后转换出来，我无法让它适用于多个参数：

wstring
fmt_msg2(const wchar_t *msg, fmt::format_args args) {
std::string s  = utf8_from_utf16(msg).c_str();
std::string s_ = fmt::vformat(s, args);
return utf16_from_utf8(s_.data());
}
wstring s = fmt_msg2(L"hey {}", 24); // works
wstring s = fmt_msg2(L"hey {} {}", 24, 58); // error
1>client.cpp
1>client.cpp(757,44): error C2660:  'fmt_msg2': function does not take 3 arguments
1>client.cpp(757,44): error C2660:   wstring s = fmt_msg2(L"hey {} {}", 24, 58);
1>client.cpp(757,44): error C2660:                                            ^
1>typedefs.h(109,9): message :  see declaration of 'fmt_msg2'
1>typedefs.h(109,9): message : wstring fmt_msg2(wchar_t cc *msg, fmt::format_args args);
1>typedefs.h(109,9): message :         ^

我还发现提到了 fmt：：MemoryWriter，它可能有助于我格式化为 wchar_t[]，但看起来它不再可用了？

不知道还能尝试什么。

更新

在用新鲜的眼光看了之后，我意识到我并没有包装fmt_msg2——所以现在我有了这个：

在 typedefs.h 文件中：

ea::wstring vfmt_msg3(const ea::wstring &msg, fmt::wformat_args args);
template <typename... Args>
ea::wstring
fmt_msg3(const ea::wstring &format, const Args &... args) {
return vfmt_msg3(format, fmt::make_format_args<fmt::wformat_args>(args...));
}

在客户端.cpp文件中：

ea::wstring
vfmt_msg3(const ea::wstring &msg, fmt::wformat_args args) {
std::wstring s_ = fmt::vformat(std::wstring(msg.data()), args);
return ea::wstring(s_.data());
}
wstring s = fmt_msg3(L"hey {} {}", 24, 58);

但是在Visual Studio 16.2.0上，我收到以下错误：

core.h(687,39): error C2039:  'char_type': is not a member of 'fmt::v5::wformat_args'
core.h(687,39): error C2039:   using char_type = typename Context::char_type;
core.h(687,39): error C2039:                                       ^ (compiling source file client.cpp)
core.h(1216): message :  see declaration of 'fmt::v5::wformat_args'
core.h(1216): message : struct wformat_args : basic_format_args<wformat_context> { (compiling source file client.cpp)
core.h(1095): message :  see reference to class template instantiation 'fmt::v5::internal::value<Context>' being compiled
core.h(1095): message :         with
core.h(1095): message :         [
core.h(1095): message :             Context=fmt::v5::wformat_args
core.h(1095): message :         ]
core.h(1095): message :   value_type data_[num_args + (!is_packed || num_args == 0 ? 1 : 0)]; (compiling source file client.cpp)
typedefs.h(119): message :  see reference to class template instantiation 'fmt::v5::format_arg_store<fmt::v5::wformat_args,int,int>' being compiled
typedefs.h(119): message : fmt_msg3(const ea::wstring &format, const Args &... args) { (compiling source file client.cpp)
client.cpp(757): message :  see reference to function template instantiation 'eastl::wstring fmt_msg3<int,int>(const eastl::wstring &,const int &,const int &)' being compiled
client.cpp(757): message :   wstring s = fmt_msg3(L"hey {} {}", 24, 58);