SDL_IOStreamInterface

typedef struct SDL_IOStreamInterface {  /* The version of this interface */  Uint32 version;   /**  * Return the number of bytes in this SDL_IOStream  *  * \return the total size of the data stream, or -1 on error.  */  Sint64 (SDLCALL *size)(void *userdata);   /**  * Seek to `offset` relative to `whence`, one of stdio's whence values:  * SDL_IO_SEEK_SET, SDL_IO_SEEK_CUR, SDL_IO_SEEK_END  *  * \return the final offset in the data stream, or -1 on error.  */  Sint64 (SDLCALL *seek)(void *userdata, Sint64 offset, SDL_IOWhence whence);   /**  * Read up to `size` bytes from the data stream to the area pointed  * at by `ptr`. `size` will always be > 0.  *  * On an incomplete read, you should set `*status` to a value from the  * SDL_IOStatus enum. You do not have to explicitly set this on  * a complete, successful read.  *  * \return the number of bytes read  */  size_t (SDLCALL *read)(void *userdata, void *ptr, size_t size, SDL_IOStatus *status);   /**  * Write exactly `size` bytes from the area pointed at by `ptr`  * to data stream. `size` will always be > 0.  *  * On an incomplete write, you should set `*status` to a value from the  * SDL_IOStatus enum. You do not have to explicitly set this on  * a complete, successful write.  *  * \return the number of bytes written  */  size_t (SDLCALL *write)(void *userdata, const void *ptr, size_t size, SDL_IOStatus *status);   /**  * If the stream is buffering, make sure the data is written out.  *  * On failure, you should set `*status` to a value from the  * SDL_IOStatus enum. You do not have to explicitly set this on  * a successful flush.  *  * \return true if successful or false on write error when flushing data.  */  bool (SDLCALL *flush)(void *userdata, SDL_IOStatus *status);   /**  * Close and free any allocated resources.  *  * This does not guarantee file writes will sync to physical media; they  * can be in the system's file cache, waiting to go to disk.  *  * The SDL_IOStream is still destroyed even if this fails, so clean up anything  * even if flushing buffers, etc, returns an error.  *  * \return true if successful or false on write error when flushing data.  */  bool (SDLCALL *close)(void *userdata);  } SDL_IOStreamInterface;