而std::format_to和std::format_to_n则需要指定格式化之后字符串的输出位置,后者还需指定截取的字符长度。 例子中指定了输出位置为std::string,截取长度为6,所以有了如上输出。 在std::format和std::format_to内部则使用了std::vformat和std::vformat_to,实现如下: 1template<class... _Types> 2stringforma...
fmt::format_to can use FMT_STRING to validate the format string, while formatting to a fmt::memory_buffer to avoid allocating a std::string. This works successfully for built-in types but fails to compile for user-defined types with a 'c...
值得称赞的是，fmtlib的print方法支持打印UTF-8字符，这使得中文、日文等非英文字符的输出变得简单、无误。然而，fmtlib并不支持std string lib的字面值类型，这是其目前的局限之一。对于需要向容器中尾插元素的需求，std::back_inserter提供了解决方案，结合format_to可实现先组合字符串再执行尾插的操作。
The library is pretty fast, but slower on integer formatting than fmt::format_to with format string compilation on Karma's own benchmark, see Converting a hundred million integers to strings per second.License{fmt} is distributed under the MIT license....
fmt::format_to(buf, fmt("{:d}"), "foo"); Moved experimental color support tofmt/color.hand enabled the new API by default. The old API can be enabled by defining theFMT_DEPRECATED_COLORSmacro. Added formatting support for types explicitly convertible tofmt::string_view: ...
Some simple format string examples:"First, thou shalt count to {0}" // References the first argument "Bring me a {}" // Implicitly references the first argument "From {} to {}" // Same as "From {0} to {1}" The format_spec field contains a specification of how the value should...
std::format会返回一个std::string,所以可以通过cout直接输出格式化之后的字符串。 而std::format_to和std::format_to_n则需要指定格式化之后字符串的输出位置,后者还需指定截取的字符长度。 例子中指定了输出位置为std::string,截取长度为6,所以有了如上输出。
FMT_INLINE auto format_to(char (&out)[N], format_string<T...> fmt, T&&... args) -> format_to_result<char*> { return vformat_to(out, fmt, fmt::make_format_args(args...)); auto result = fmt::format_to_n(out, N, fmt, static_cast<T&&>(args)...); return {result.out...
Consider the following example of formatting to a fixed size buffer before writing to stdout: #include <fmt/format.h> #include <unistd.h> void vlog(fmt::string_view format, fmt::format_args args) { char line[1024]; auto [_, size] = fmt::...
constexpr inline void LOG(int prio, const char* tag, fmt::format_string<T...> fmt, T&&... args) { std::array<char, 1024> buf{}; auto s = fmt::format_to_n(buf.data(), buf.size(), fmt, std::forward<T>(args)...).size; buf[s] = '\0'; __android_log_write(prio, ...