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Add small EXAMPLE section to bsearch.3.

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Submitted by:		fernape (via Phabricator)
Reviewed by:		bcr, jilles, dab
Approved by:		bcr (man pages), jilles (src)
MFC after:		3 days
Differential Revision:	https://reviews.freebsd.org/D19902
This commit is contained in:
Benedict Reuschling 2019-05-15 15:54:27 +00:00
parent 6aa63d8dbe
commit 15c9c06e6a
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=347617
1 changed files with 56 additions and 1 deletions
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57
lib/libc/stdlib/bsearch.3
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@ -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 ,