SDL_MS_TO_NS - Man Page

#include <SDL3/SDL_timer.h>

#define SDL_MS_TO_NS(MS)        (((Uint64)(MS)) * SDL_NS_PER_MS)

This only converts whole numbers, not fractional milliseconds.

MS

the number of milliseconds to convert.

Returns MS, expressed in nanoseconds.

It is safe to call this macro from any thread.

This macro is available since SDL 3.2.0.