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LSEARCH(3) FreeBSD Library Functions Manual LSEARCH(3)
NAME
lsearch, lfind - linear search and append
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <search.h>
void *
lsearch(const void *key, void *base, size_t *nelp, size_t width,
int (*compar)(const void *, const void *));
void *
lfind(const void *key, const void *base, size_t *nelp, size_t width,
int (*compar)(const void *, const void *));
DESCRIPTION
The lsearch() and lfind() functions walk linearly through an array and
compare each element with the one to be sought using a supplied
comparison function.
The key argument points to an element that matches the one that is
searched. The array's address in memory is denoted by the base argument.
The width of one element (i.e., the size as returned by sizeof()) is
passed as the width argument. The number of valid elements contained in
the array (not the number of elements the array has space reserved for)
is given in the integer pointed to by nelp. The compar argument points
to a function which compares its two arguments and returns zero if they
are matching, and non-zero otherwise.
If no matching element was found in the array, lsearch() copies key into
the position after the last element and increments the integer pointed to
by nelp.
RETURN VALUES
The lsearch() and lfind() functions return a pointer to the first element
found. If no element was found, lsearch() returns a pointer to the newly
added element, whereas lfind() returns NULL. Both functions return NULL
if an error occurs.
EXAMPLES
#include <search.h>
#include <stdio.h>
#include <stdlib.h>
static int
element_compare(const void *p1, const void *p2)
{
int left = *(const int *)p1;
int right = *(const int *)p2;
return (left - right);
}
int
main(int argc, char **argv)
printf("Enter a number: ");
if (scanf("%d", &key) != 1) {
printf("Bad input\n");
return (EXIT_FAILURE);
}
element = lfind(&key, array, &array_size, element_size,
element_compare);
if (element != NULL)
printf("Element found: %d\n", *(int *)element);
else
printf("Element not found\n");
return (EXIT_SUCCESS);
}
SEE ALSO
bsearch(3), hsearch(3), tsearch(3)
STANDARDS
The lsearch() and lfind() functions conform to IEEE Std 1003.1-2001
("POSIX.1").
HISTORY
The lsearch() and lfind() functions appeared in 4.2BSD. In FreeBSD 5.0,
they reappeared conforming to IEEE Std 1003.1-2001 ("POSIX.1").
FreeBSD 14.0-RELEASE-p6 April 17, 2016 FreeBSD 14.0-RELEASE-p6