Add system's polling infrastructure to be notified whenever a
file descriptor is ready to be read from or written to.
Adds a few classes:
* Poller, as an interface to epoll()
* Pollable, as an interface to a file descriptor
Add DEFINE prefix, since this macro is defining these operators and
remove the parameter since we will always use it to access a
union/struct as a byte array.
Revert these commits:
"AP_Common: gcc 4.9.2 behaves differently from 4.9.3"
"AP_Common: this workaround for missing/cmath is also needed for gcc 4.9.3"
This breaks the build for PX4. The change is related to the libc, not
the compiler version. We have an workaround there based on compiler
version just because it's usual to have a more recent libc version when
you have a recent compiler.
The way the build was fixed for gcc >= 5.3 breaks the build for older
compiler versions on waf. Fix this by ifdef'ing for WAF_BUILD and
checking the compiler version.
The new function can deal with a variable number of function parameters.
Additionally, I renamed the functions to norm(), because this is the
standard name used in several other projects.
This header is used by waf to contain the generated version macros,
particularly using the git hash. For waf it's better to be in a separate
header since it then can keep track of changes on it a trigger
recompilation.
For the make build system, a dummy ap_version.h file has been added in
the missing/ folder so both implementations can co-exist.
Add a cstddef header to allow using std::nullptr_t with those toolchains
that don't provide it. The idea is to make these platforms to use our
wrapper header (see https://gcc.gnu.org/onlinedocs/cpp/Wrapper-Headers.html)
and then we add the missing bits to the header.
Let the warning flag be added by the build system and not when/if the
header AP_Common.h is included. Both waf and make were already updated
to contain these warnings. Besides being in the wrong place, with
clang++ we actually can't add "-Wno-" definitions in build system
because we enable all of the in the header with -Wall.
As commented in 8218140 ("AP_Common: add scanf format macro"), "FORMAT"
was a bad name for this macro since there's also the scanf. Rename to
FMT_PRINTF to follow the scanf name.
Add a macro to annotate functions that act like scanf. Calling the
printf format macro as FORMAT was bad as can be seen now. Later we need
to rename it to FMT_PRINTF.