Unlike the relatively non-invasive old way of capturing stdout/stderr,
this new way is also able to capture output from C's stdlib functions
such as `printf`. This is done by redirecting stdout and stderr file
descriptors to a file, and then reading this file back.
This approach has two sizeable drawbacks:
1) Performance, obviously. Previously an installed capture made the
program run faster (as long as it was then discarded), because a call
to `std::cout` did not result in text output to the console. This new
capture method in fact forces disk IO. While it is likely that any
modern OS will keep this file in memory-cache and might never actually
issue the IO to the backing storage, it is still a possibility and
calls to the file system are not free.
2) Nonportability. While POSIX is usually assumed portable, and this
implementation relies only on a very common parts of it, it is no
longer standard C++ (or just plain C) and thus might not be available
on some obscure platforms. Different C libs might also implement the
relevant functions in a less-than-useful ways (e.g. MS's `tmpfile`
generates a temp file inside system folder, so it will not work
without elevated privileges and thus is useless).
These two drawbacks mean that, at least for now, the new capture is
opt-in. To opt-in, `CATCH_CONFIG_EXPERIMENTAL_REDIRECT` needs to be
defined in the implementation file.
Closes#1243
Also hides std::chrono, std::pair and std::chrono::* behind
new configuration macros, CATCH_CONFIG_ENABLE_*_STRINGMAKER
to avoid dragging in <utility>, <tuple> and <chrono> in common
path, unless requested.
* Assertions are defined into (void)(0) no-op
* SECTIONs are defined away (leaving {} as scope)
* TEST_CASEs and TEST_CASE_METHODs are not registered.
* REGISTER_TEST_CASE is defined into (void)(0) no-op
* METHOD_AS_TEST_CASE is defined away
The toggle is `CATCH_CONFIG_DISABLE_MATCHERS` and the only use is
to speed up compilation of small TUs. For large ones it is likely
insignificant, because the speed up is constant relative to
number of tests/assertions in TU.
Some versions of MinGW do not support enough of Win32 API to let us work
with SEH, so SEH is now MSVC only (+ configurable toggle).
Also made use of gmtime_s MSVC only (as oposed to Windows only).
Fixes#805
