Date: Wed, 24 Jul 2019 06:29:19 +0000 (UTC) From: Konstantin Belousov <kib@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: r350272 - stable/12/lib/libc/stdlib Message-ID: <201907240629.x6O6TJRr046870@repo.freebsd.org>
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Author: kib Date: Wed Jul 24 06:29:19 2019 New Revision: 350272 URL: https://svnweb.freebsd.org/changeset/base/350272 Log: MFC r350091: bsearch.3: Improve the example 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 Wed Jul 24 04:48:04 2019 (r350271) +++ stable/12/lib/libc/stdlib/bsearch.3 Wed Jul 24 06:29:19 2019 (r350272) @@ -32,7 +32,7 @@ .\" @(#)bsearch.3 8.3 (Berkeley) 4/19/94 .\" $FreeBSD$ .\" -.Dd May 15, 2019 +.Dd July 17, 2019 .Dt BSEARCH 3 .Os .Sh NAME @@ -93,26 +93,29 @@ A sample program that searches people by age in a sort #include <string.h> struct person { - char name[5]; - int age; + const char *name; + int age; }; -int -compare(const void *key, const void *array_member) +static int +compare(const void *a, const void *b) { - int age = (intptr_t) key; - struct person person = *(struct person *) array_member; + const int *age; + const struct person *person; - return (age - person.age); + age = a; + person = b; + + return (*age - person->age); } int -main() +main(void) { struct person *friend; - + int age; /* Sorted array */ - struct person friends[6] = { + const struct person friends[] = { { "paul", 22 }, { "anne", 25 }, { "fred", 25 }, @@ -120,22 +123,28 @@ main() { "mark", 35 }, { "bill", 50 } }; + const size_t len = sizeof(friends) / sizeof(friends[0]); - size_t array_size = sizeof(friends) / sizeof(struct person); - - friend = bsearch((void *)22, &friends, array_size, sizeof(struct person), compare); + age = 22; + friend = bsearch(&age, friends, len, sizeof(friends[0]), 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); + age = 25; + friend = bsearch(&age, friends, len, sizeof(friends[0]), compare); + + /* + * For multiple elements with the same key, it is implementation + * defined which will be returned + */ + 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); + age = 30; + friend = bsearch(&age, friends, len, sizeof(friends[0]), compare); assert(friend == NULL); printf("friend aged 30 not found\en"); - - return (EXIT_SUCCESS); } .Ed .Sh SEE ALSO
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