mirror of
https://github.com/fmtlib/fmt.git
synced 2024-12-26 18:28:20 +00:00
Update docs
This commit is contained in:
parent
4d0aa4d8fe
commit
05a28312cf
@ -17,8 +17,8 @@
|
||||
:alt: Ask questions at StackOverflow with the tag fmt
|
||||
:target: https://stackoverflow.com/questions/tagged/fmt
|
||||
|
||||
**{fmt}** is an open-source formatting library for C++.
|
||||
It can be used as a safe and fast alternative to (s)printf and iostreams.
|
||||
**{fmt}** is an open-source formatting library providing a fast and safe
|
||||
alternative to C stdio and C++ iostreams.
|
||||
|
||||
If you like this project, please consider donating to BYSOL,
|
||||
an initiative to help victims of political repressions in Belarus:
|
||||
|
@ -48,21 +48,19 @@ The ``fmt::print`` function performs formatting and writes the result to a strea
|
||||
|
||||
fmt::print(stderr, "System error code = {}\n", errno);
|
||||
|
||||
The file argument can be omitted in which case the function prints to
|
||||
``stdout``:
|
||||
If you omit the file argument the function will print to ``stdout``:
|
||||
|
||||
.. code:: c++
|
||||
|
||||
fmt::print("Don't {}\n", "panic");
|
||||
|
||||
The Format API also supports positional arguments useful for localization:
|
||||
The format API also supports positional arguments useful for localization:
|
||||
|
||||
.. code:: c++
|
||||
|
||||
fmt::print("I'd rather be {1} than {0}.", "right", "happy");
|
||||
|
||||
Named arguments can be created with ``fmt::arg``. This makes it easier to track
|
||||
what goes where when multiple arguments are being formatted:
|
||||
You can pass named arguments with ``fmt::arg``:
|
||||
|
||||
.. code:: c++
|
||||
|
||||
@ -91,16 +89,17 @@ time. For example, the code
|
||||
|
||||
fmt::format("The answer is {:d}", "forty-two");
|
||||
|
||||
throws a ``format_error`` exception with description "unknown format code 'd' for
|
||||
string", because the argument ``"forty-two"`` is a string while the format code
|
||||
``d`` only applies to integers, while
|
||||
throws the ``format_error`` exception because the argument ``"forty-two"`` is a
|
||||
string while the format code ``d`` only applies to integers.
|
||||
|
||||
The code
|
||||
|
||||
.. code:: c++
|
||||
|
||||
format(FMT_STRING("The answer is {:d}"), "forty-two");
|
||||
|
||||
reports a compile-time error for the same reason on compilers that support
|
||||
relaxed ``constexpr``. See `here <api.html#c.fmt>`_ for details.
|
||||
reports a compile-time error on compilers that support relaxed ``constexpr``.
|
||||
See `here <api.html#c.fmt>`_ for details.
|
||||
|
||||
The following code
|
||||
|
||||
@ -117,13 +116,13 @@ formatted into a narrow string. You can use a wide format string instead:
|
||||
|
||||
For comparison, writing a wide character to ``std::ostream`` results in
|
||||
its numeric value being written to the stream (i.e. 1070 instead of letter 'ю'
|
||||
which is represented by ``L'\x42e'`` if we use Unicode) which is rarely what is
|
||||
needed.
|
||||
which is represented by ``L'\x42e'`` if we use Unicode) which is rarely
|
||||
desirable.
|
||||
|
||||
Compact Binary Code
|
||||
-------------------
|
||||
|
||||
The library is designed to produce compact per-call compiled code. For example
|
||||
The library produces compact per-call compiled code. For example
|
||||
(`godbolt <https://godbolt.org/g/TZU4KF>`_),
|
||||
|
||||
.. code:: c++
|
||||
@ -144,8 +143,8 @@ compiles to just
|
||||
mov rcx, rsp
|
||||
mov edi, offset .L.str
|
||||
mov esi, 17
|
||||
mov edx, 2
|
||||
call fmt::v5::vprint(fmt::v5::basic_string_view<char>, fmt::v5::format_args)
|
||||
mov edx, 1
|
||||
call fmt::v7::vprint(fmt::v7::basic_string_view<char>, fmt::v7::format_args)
|
||||
xor eax, eax
|
||||
add rsp, 24
|
||||
ret
|
||||
@ -167,20 +166,19 @@ The library is highly portable and relies only on a small set of C++11 features:
|
||||
* deleted functions
|
||||
* alias templates
|
||||
|
||||
These are available since GCC 4.8, Clang 3.0 and MSVC 19.0 (2015). For older
|
||||
compilers use {fmt} `version 4.x
|
||||
<https://github.com/fmtlib/fmt/releases/tag/4.1.0>`_ which continues to be
|
||||
maintained and only requires C++98.
|
||||
These are available in GCC 4.8, Clang 3.0, MSVC 19.0 (2015) and more recent
|
||||
compiler version. For older compilers use {fmt} `version 4.x
|
||||
<https://github.com/fmtlib/fmt/releases/tag/4.1.0>`_ which is maintained and
|
||||
only requires C++98.
|
||||
|
||||
The output of all formatting functions is consistent across platforms. In
|
||||
particular, formatting a floating-point infinity always gives ``inf`` while the
|
||||
output of ``printf`` is platform-dependent. For example,
|
||||
The output of all formatting functions is consistent across platforms.
|
||||
For example,
|
||||
|
||||
.. code::
|
||||
|
||||
fmt::print("{}", std::numeric_limits<double>::infinity());
|
||||
|
||||
always prints ``inf``.
|
||||
always prints ``inf`` while the output of ``printf`` is platform-dependent.
|
||||
|
||||
.. _ease-of-use:
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user