Change mingw-w64 printf format checks in public curl headers to use
`__MINGW_PRINTF_FORMAT` instead of `gnu_printf`. This syncs the format
checker with format string macros published via `curl/system.h`. (Also
disable format checks for mingw-w64 older than 3.0.0 (2013-09-20) and
classic-mingw, which do not support this macro.)
This fixes bogus format checker `-Wformat` warnings in 3rd party code
using curl format strings with the curl printf functions, when using
mingw-w64 7.0.0 (2019-11-10) and older (with GCC, MSVCRT).
It also allows to delete two workaounds for this within curl itself:
- setting `-D__USE_MINGW_ANSI_STDIO=1` for mingw-w64 via cmake and
configure for `docs/examples` and `tests/http/clients`.
Ref: c730c8549b#14640
The format check macro is incompatible (depending on mingw-w64 version
and configuration) with the C99 `%z` (`size_t`) format string used
internally by curl.
To work around this problem, override the format check style in curl
public headers to use `gnu_printf`. This is compatible with `%z` in all
mingw-w64 versions and allows keeping the C99 format strings internally.
Also:
- lib/ws.c: add missing space to an error message.
- docs/examples/ftpgetinfo.c: fix to use standard printf.
Ref: #14643 (take 1)
Follow-up to 3829759bd0#12489Closes#14703
This directory is for libcurl programming examples. They are meant to show
some simple steps on how you can build your own application to take full
advantage of libcurl.
If you end up with other small but still useful example sources, please mail
them for submission in future packages and on the website.
Building
The Makefile.example is an example Makefile that could be used to build
these examples. Just edit the file according to your system and requirements
first.
Most examples should build fine using a command line like this:
`curl-config --cc --cflags --libs` -o example example.c
Some compilers do not like having the arguments in this order but instead
want you do reorganize them like:
`curl-config --cc` -o example example.c `curl-config --cflags --libs`
Please do not use the curl.se site as a test target for your libcurl
applications/experiments. Even if some of the examples use that site as a URL
at some places, it does not mean that the URLs work or that we expect you to
actually torture our website with your tests. Thanks.
Examples
Each example source code file is designed to be and work stand-alone and
rather self-explanatory. The examples may at times lack the level of error
checks you need in a real world, but that is then only for the sake of
readability: to make the code smaller and easier to follow.
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