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Update README.rst

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Victor Zverovich 2019-11-20 09:33:59 -08:00 committed by GitHub
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@ -81,16 +81,15 @@ Check a format string at compile time:
.. code:: c++
// test.cc
#define FMT_STRING_ALIAS 1
#include <fmt/format.h>
std::string s = format(fmt("{2}"), 42);
std::string s = format(FMT_STRING("{2}"), 42);
.. code::
$ c++ -Iinclude -std=c++14 test.cc
...
test.cc:4:17: note: in instantiation of function template specialization 'fmt::v5::format<S, int>' requested here
std::string s = format(fmt("{2}"), 42);
std::string s = format(FMT_STRING("{2}"), 42);
^
include/fmt/core.h:778:19: note: non-constexpr function 'on_error' cannot be used in a constant expression
ErrorHandler::on_error(message);
@ -122,11 +121,10 @@ Format objects of user-defined types via a simple `extension API
template <>
struct fmt::formatter<date> {
template <typename ParseContext>
constexpr auto parse(ParseContext &ctx) { return ctx.begin(); }
constexpr auto parse(format_parse_context& ctx) { return ctx.begin(); }
template <typename FormatContext>
auto format(const date &d, FormatContext &ctx) {
auto format(const date& d, FormatContext& ctx) {
return format_to(ctx.out(), "{}-{}-{}", d.year, d.month, d.day);
}
};
@ -142,12 +140,12 @@ which take arbitrary arguments (`godbolt <https://godbolt.org/g/MHjHVf>`_):
.. code:: c++
// Prints formatted error message.
void vreport_error(const char *format, fmt::format_args args) {
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) {
void report_error(const char* format, const Args & ... args) {
vreport_error(format, fmt::make_format_args(args...));
}
@ -210,7 +208,6 @@ printf 2.6 29 26
printf+string 16.4 29 26
iostreams 31.1 59 55
{fmt} 19.0 37 34
tinyformat 44.0 103 97
Boost Format 91.9 226 203
Folly Format 115.7 101 88
============= =============== ==================== ==================
@ -231,14 +228,13 @@ printf 2.2 33 30
printf+string 16.0 33 30
iostreams 28.3 56 52
{fmt} 18.2 59 50
tinyformat 32.6 88 82
Boost Format 54.1 365 303
Folly Format 79.9 445 430
============= =============== ==================== ==================
``libc``, ``lib(std)c++`` and ``libfmt`` are all linked as shared libraries to
compare formatting function overhead only. Boost Format and tinyformat are
header-only libraries so they don't provide any linkage options.
compare formatting function overhead only. Boost Format is a
header-only library so it doesn't provide any linkage options.
Running the tests
~~~~~~~~~~~~~~~~~
@ -424,20 +420,6 @@ arguments. However it has significant limitations, citing its author:
It is also quite big and has a heavy dependency, STLSoft, which might be
too restrictive for using it in some projects.
Loki SafeFormat
~~~~~~~~~~~~~~~
SafeFormat is a formatting library which uses ``printf``-like format strings and
is type safe. It doesn't support user-defined types or positional arguments and
makes unconventional use of ``operator()`` for passing format arguments.
Tinyformat
~~~~~~~~~~
This library supports ``printf``-like format strings and is very small .
It doesn't support positional arguments and wrapping it in C++98 is somewhat
difficult. Tinyformat relies on iostreams which limits its performance.
Boost Spirit.Karma
~~~~~~~~~~~~~~~~~~