On 09/16/2016 10:03 PM, Mats Wichmann wrote: > On 09/16/2016 03:06 AM, Ori Avtalion wrote: >> Hi, >> >> None of the function signatures in man pages list the "restrict" >> keywords, even if the actual function signatures in the headers have >> them. >> >> Some example functions that use "restrict": >> * memcpy (src and dest must not overlap) >> * strtod >> >> Is this an intentional omission? > > It's an interesting question. These largely come from ISO C, and I > recall reading that glibc developers consider the qualifier rather > useless, noting something like "since ISO C uses it, we have to also". > > This is one of the interesting pieces of text in ISO C11 on it (6.7.3): > > An object that is accessed through a restrict-qualified pointer has a > special association with that pointer. This association, defined in > 6.7.3.1 below, requires that all accesses to that object use, directly > or indirectly, the value of that particular ponter. 135) The intended > use of the restrict qualifier (like the register storage class) is to > promote optimization, and deleting all instances of the qualifier from > all preprocessing translation units composing a conforming program does > not change its meaning (i.e., observable behavior). > > > So you could argue that since there is no behavioral change from > adding/omitting it, it doesn't help programmers when used in the manpage > functions signatures. But that's just me noodling out loud. You could > also argue that since ISO C uses it, glibc headers use it, and POSIX > pages use it it's kind of silly to leave restrict out. I'm sort of on the fence about it. If someone volunteered to fix all the pages, we could discuss it, but I have no time for this at the moment myself. Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
