Update docs

This commit is contained in:
Victor Zverovich 2020-09-30 17:38:28 -07:00
parent 4d0aa4d8fe
commit 05a28312cf
2 changed files with 23 additions and 25 deletions

View File

@ -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:

View File

@ -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: