Date: Sat, 18 May 2019 03:15:08 +0000 (UTC) From: Benedict Reuschling <bcr@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r347951 - stable/12/lib/libc/stdlib Message-ID: <201905180315.x4I3F8g2080553@repo.freebsd.org>
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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; + + return (age - person.age); +} + +int +main() +{ + 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); + + friend = bsearch((void *)22, &friends, array_size, sizeof(struct person), compare); + 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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