This rolls back to the simpler version of ARRAY_SIZE. The more complex
one helps catching bugs when we use pointers when we are expecting an
array, but can't stand arrays with 0 elements. I'm not aware of bugs it
actually caught on ArduPilot, although it did for me in other projects.
I think this is better than having a separate "_SIMPLE" version of the
macro and spread its usage... the trend is just to use the simpler
version anyway.
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.
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.
Now that most places in the code use the ARRAY_SIZE macro instead of
coding it by hand, let's use some type safety in its definition. This is
a C++ version of similar macros used in kmod, Linux kernel and the
source of them, ccan.
A C++ version like this is used in V8 (the JS engine) and other open
source projects.
The main benefit of this version is that you get a compile error if you
pass in a variable that's not an array. For example,
Bla y[10];
Bla *y_ptr = y;
void foo(Bla x[])
{
// build error since x[] decay to a pointer in function
// parameter
for (int i = 0; i < ARRAY_SIZE(x); i++) {
...
}
// build error since y_ptr is not an array
for (int i = 0; i < ARRAY_SIZE(y_ptr); i++) {
...
}
}
I added the additional specialization to allow arrays of size 0.
Andrew Tridgell
Lucas De Marchi
Peter Barker
Francisco Ferreira
Dr.-Ing. Amilcar Do Carmo Lucas
Patrick José Pereira
Lucas De Marchi
murata
Mathieu OTHACEHE
Gustavo Jose de Sousa
Tom Pittenger
Ricardo de Almeida Gonzaga
Randy Mackay
Grant Morphett
Andrew Tridgell
Victor Mayoral Vilches
Emile Castelnuovo