On Sat, 4 Apr 2020 at 01:44, Vaibhav Gupta <vaibhav.varo...@gmail.com> wrote: > > > > On Sat, Apr 4, 2020, 1:41 AM Vijay Kumar Banerjee <vi...@rtems.org> wrote: >> >> >> >> On Sat, Apr 4, 2020 at 1:22 AM Vaibhav Gupta <vaibhav.varo...@gmail.com> >> wrote: >>> >>> CPP directives like: >>> 1) #if >>> 2) #ifdef >>> 3) #ifndef >>> 4) #elif >>> 5) #else >>> 6) #endif >>> >>> do form code blocks. Since, they don't make use of brackets, >>> as a part of C language rule, their nested and repeated use >>> can make the code very hard to read. Can even result it >>> spaghetti code. >>> >>> This can be understood by this patch: >>> https://lists.rtems.org/pipermail/devel/2020-April/058964.html >>> >>> The proposed idea is: >>> 1) Nested CPP directives should follow same indentation rules >>> as of nested conditional statements like 'if' and loops. >>> >>> 2) To mark which closing CPP directive (#endif) pairs with which >>> opening CPP directive (#if or #ifdef or #ifndef), make use of comments. >>> ex: >>> #ifdef <some-macro> /* To test/verify/enable xyz */ >>> ..... >>> .... >>> #endif /* To test/verify/enable xyz */ >>> >> There's a rule like this in the FreeBSD > > Yes, and when I ported APIs, last year, as a part of my > Project, the ported headers follow same rule. >> >> and we follow it in RTEMS-libbsd. >> It is nicely explained in the FreeBSD style guide so I'm pasting an excerpt >> below: > > Thanks! > > --Vaibhav Gupta >> >> >> " >> The comment for #endif should match the expression used in the corre- >> sponding #if or #ifdef. The comment for #else and #elif should match >> the >> inverse of the expression(s) used in the preceding #if and/or #elif >> statements. In the comments, the subexpression "defined(FOO)" is abbre- >> viated as "FOO". For the purposes of comments, "#ifndef FOO" is treated >> as "#if !defined(FOO)". >> >> #ifdef KTRACE >> #include <sys/ktrace.h> >> #endif >> >> #ifdef COMPAT_43 >> /* A large region here, or other conditional code. */ >> #else /* !COMPAT_43 */ >> /* Or here. */ >> #endif /* COMPAT_43 */ >> >> #ifndef COMPAT_43 >> /* Yet another large region here, or other conditional code. */ >> #else /* COMPAT_43 */ >> /* Or here. */ >> #endif /* !COMPAT_43 */ >> >> " >> >> It would be nice to have a rule like this for RTEMS codes as well. >> >> >>> --Vaibhav Gupta
Should it be included then? -- Vaibhav Gupta _______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel
