https://bugs.exim.org/show_bug.cgi?id=1918
Giuseppe D'Angelo <dangelog@???> changed:
What |Removed |Added
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CC| |dangelog@???
--- Comment #4 from Giuseppe D'Angelo <dangelog@???> ---
The advantage at using enums rather than #defines is to make it a compile-time
error (warning?) if you pass an invalid value for a given API call.
To elaborate: right now we have
int pcre2_config(uint32_t what, void *where);
and a bunch of #defines for symbolic constants you can pass to "what".
The problem is that this is has loose typing, so you can happily pass *any*
integer, in particular integers obtained by using the wrong #define.
/* PCRE2_CASELESS is for pcre2_compile, not for pcre2_config! */
pcre2_config(PCRE2_CASELESS, ...);
What's worse, this may or may not result in a runtime error, depending on
whether you accidentally passed a valid value (albeit obtained through the
wrong define, which should still be reported to the programmer as a potential
problem!).
The right way to do this is using enums:
enum pcre2_config_what { pcre2_config_this, pcre2_config_that };
int pcre2_config(enum pcre2_config_what, void *where);
/* now I must pass exactly one of the enumerators or the code doesn't
compile */
Of course it's too late to do this now. This is an API and ABI break. Maybe for
PCRE3? :P
Last, but not least: unfortunately C has not a type-safe solution for bitmasks.
(C++ has.)
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