(This is the documentation for SDL3, which is the current stable version. SDL2 was the previous version!)

SDL_bsearch_r

Perform a binary search on a previously sorted array, passing a userdata pointer to the compare function.

Header File

Syntax

void * SDL_bsearch_r(const void *key, const void *base, size_t nmemb, size_t size, SDL_CompareCallback_r compare, void *userdata);

Function Parameters

const void *	key	a pointer to a key equal to the element being searched for.
const void *	base	a pointer to the start of the array.
size_t	nmemb	the number of elements in the array.
size_t	size	the size of the elements in the array.
SDL_CompareCallback_r	compare	a function used to compare elements in the array.
void *	userdata	a pointer to pass to the compare function.

Return Value

(void *) Returns a pointer to the matching element in the array, or NULL if not found.

Remarks

For example:

typedef enum {
    sort_increasing,
    sort_decreasing,
} sort_method;

typedef struct {
    int key;
    const char *string;
} data;

int SDLCALL compare(const void *userdata, const void *a, const void *b)
{
    sort_method method = (sort_method)(uintptr_t)userdata;
    const data *A = (const data *)a;
    const data *B = (const data *)b;

    if (A->key < B->key) {
        return (method == sort_increasing) ? -1 : 1;
    } else if (B->key < A->key) {
        return (method == sort_increasing) ? 1 : -1;
    } else {
        return 0;
    }
}

data values[] = {
    { 1, "first" }, { 2, "second" }, { 3, "third" }
};
data key = { 2, NULL };

data *result = SDL_bsearch_r(&key, values, SDL_arraysize(values), sizeof(values[0]), compare, (const void *)(uintptr_t)sort_increasing);

Thread Safety

It is safe to call this function from any thread.

Version

This function is available since SDL 3.1.3.