Date: Sat, 18 May 2019 11:28:38 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Benedict Reuschling <bcr@FreeBSD.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: Re: svn commit: r347951 - stable/12/lib/libc/stdlib Message-ID: <20190518082838.GW2748@kib.kiev.ua> In-Reply-To: <201905180315.x4I3F8g2080553@repo.freebsd.org> References: <201905180315.x4I3F8g2080553@repo.freebsd.org>
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On Sat, May 18, 2019 at 03:15:08AM +0000, Benedict Reuschling wrote: > Author: bcr (doc committer) > Date: Sat May 18 03:15:07 2019 > New Revision: 347951 > URL: https://svnweb.freebsd.org/changeset/base/347951 > > Log: > MFC r347617: > Add small EXAMPLE section to bsearch.3. > > Submitted by: fernape (via Phabricator) > Reviewed by: bcr, jilles, dab > Approved by: bcr (man pages), jilles (src) > Differential Revision: https://reviews.freebsd.org/D19902 > > Modified: > stable/12/lib/libc/stdlib/bsearch.3 > Directory Properties: > stable/12/ (props changed) > > Modified: stable/12/lib/libc/stdlib/bsearch.3 > ============================================================================== > --- stable/12/lib/libc/stdlib/bsearch.3 Sat May 18 02:02:14 2019 (r347950) > +++ stable/12/lib/libc/stdlib/bsearch.3 Sat May 18 03:15:07 2019 (r347951) > @@ -32,7 +32,7 @@ > .\" @(#)bsearch.3 8.3 (Berkeley) 4/19/94 > .\" $FreeBSD$ > .\" > -.Dd February 22, 2013 > +.Dd May 15, 2019 > .Dt BSEARCH 3 > .Os > .Sh NAME > @@ -83,6 +83,61 @@ The > function returns a pointer to a matching member of the array, or a null > pointer if no match is found. > If two members compare as equal, which member is matched is unspecified. > +.Sh EXAMPLES > +A sample program that searches people by age in a sorted array: > +.Bd -literal > +#include <assert.h> > +#include <stdint.h> > +#include <stdio.h> > +#include <stdlib.h> > +#include <string.h> > + > +struct person { > + char name[5]; > + int age; > +}; > + > +int > +compare(const void *key, const void *array_member) > +{ > + int age = (intptr_t) key; > + struct person person = *(struct person *) array_member; These two lines contain at least three style(9) bugs, and at least one warning at higher warning level. > + > + return (age - person.age); > +} > + > +int > +main() Why use K&R definition ? > +{ > + struct person *friend; > + > + /* Sorted array */ > + struct person friends[6] = { > + { "paul", 22 }, > + { "anne", 25 }, > + { "fred", 25 }, > + { "mary", 27 }, > + { "mark", 35 }, > + { "bill", 50 } > + }; > + > + size_t array_size = sizeof(friends) / sizeof(struct person); Since you used const elsewere, why did not you used it there ? > + > + friend = bsearch((void *)22, &friends, array_size, sizeof(struct person), compare); Taking address of an array is weird. Line is too long. > + assert(strcmp(friend->name, "paul") == 0); > + printf("name: %s\enage: %d\en", friend->name, friend->age); > + > + friend = bsearch((void *)25, &friends, array_size, sizeof(struct person), compare); > + assert(strcmp(friend->name, "fred") == 0 || strcmp(friend->name, "anne") == 0); > + printf("name: %s\enage: %d\en", friend->name, friend->age); > + > + friend = bsearch((void *)30, &friends, array_size, sizeof(struct person), compare); > + assert(friend == NULL); > + printf("friend aged 30 not found\en"); > + > + return (EXIT_SUCCESS); > +} > +.Ed > .Sh SEE ALSO > .Xr db 3 , > .Xr lsearch 3 ,
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