Require sizeof(bool) == 1.
The C standard says that sizeof(bool) is implementation-defined, but we
know of no current systems where it is not 1. The last known systems
seem to have been Apple macOS/PowerPC 10.5 and Microsoft Visual C++ 4,
both long defunct.
PostgreSQL has always required sizeof(bool) == 1 for the definition of
bool that it used, but previously it would define its own type if the
system-provided bool had a different size. That was liable to cause
memory layout problems when interacting with system and third-party
libraries on (by now hypothetical) computers with wider _Bool, and now
C23 has introduced a new problem by making bool a built-in datatype
(like C++), so the fallback code doesn't even compile. We could
probably work around that, but then we'd be writing new untested code
for a computer that doesn't exist.
Instead, delete the unreachable and C23-uncompilable fallback code, and
let existing static assertions fail if the system-provided bool is too
wide. If we ever get a problem report from a real system, then it will
be time to figure out what to do about it in a way that also works on
modern compilers.
Note on C++: Previously we avoided including <stdbool.h> or trying to
define a new bool type in headers that might be included by C++ code.
These days we might as well just include <stdbool.h> unconditionally:
it should be visible to C++11 but do nothing, just as in C23. We
already include <stdint.h> without C++ guards in c.h, and that falls
under the same C99-compatibility section of the C++11 standard as
<stdbool.h>, so let's remove the guards here too.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/3198438.1731895163%40sss.pgh.pa.us
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/97525bc5c8ffb31475d23955d08e9ec9c1408f33
Modified Files
--------------
configure | 41 ----------------------------
configure.ac | 9 ------
meson.build | 7 -----
src/backend/jit/llvm/llvmjit_types.c | 8 ++----
src/backend/utils/fmgr/dfmgr.c | 10 -------
src/include/c.h | 30 ++------------------
src/include/pg_config.h.in | 6 ----
src/interfaces/ecpg/include/ecpg_config.h.in | 3 --
src/interfaces/ecpg/include/ecpglib.h | 30 +-------------------
src/interfaces/ecpg/include/meson.build | 1 -
src/pl/plperl/plperl_system.h | 23 ++--------------
11 files changed, 8 insertions(+), 160 deletions(-)
