void* bsearch(const void *__key, const void *__base, size_t __nmemb, size_t __size,
int(*__compar)(const void *, const void *))
The bsearch() function searches an array of
nmemb
objects, the initial member of which is pointed
to by base
, for a member that matches the object
pointed to by key
. The size of each member of the array
is specified by 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.
The bsearch() 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.