#include <stdlib.h>
void *bsearch(const void key[.size], const void base[.size * .nmemb],
size_t nmemb, size_t size,
int (*compar)(const void [.size], const void [.size]));
The contents of the array should be in ascending sorted order according to the comparison function referenced by compar. The compar routine is expected to have two arguments which point to the key object and to an array member, in that order, and should return an integer less than, equal to, or greater than zero if the key object is found, respectively, to be less than, to match, or be greater than the array member.
| Interface | Attribute | Value |
| bsearch() | Thread safety | MT-Safe |
#include <stdio.h> #include <stdlib.h> #include <string.h>
#define ARRAY_SIZE(arr) (sizeof((arr)) / sizeof((arr)[0]))
struct mi {
int nr;
const char *name;
};
static struct mi months[] = {
{ 1, "jan" }, { 2, "feb" }, { 3, "mar" }, { 4, "apr" },
{ 5, "may" }, { 6, "jun" }, { 7, "jul" }, { 8, "aug" },
{ 9, "sep" }, {10, "oct" }, {11, "nov" }, {12, "dec" }
};
static int
compmi(const void *m1, const void *m2)
{
const struct mi *mi1 = m1;
const struct mi *mi2 = m2;
return strcmp(mi1->name, mi2->name);
}
int
main(int argc, char *argv[])
{
qsort(months, ARRAY_SIZE(months), sizeof(months[0]), compmi);
for (size_t i = 1; i < argc; i++) {
struct mi key;
struct mi *res;
key.name = argv[i];
res = bsearch(&key, months, ARRAY_SIZE(months),
sizeof(months[0]), compmi);
if (res == NULL)
printf("'%s': unknown month\n", argv[i]);
else
printf("%s: month #%d\n", res->name, res->nr);
}
exit(EXIT_SUCCESS);
}