diff --git a/soundio/soundio.h b/soundio/soundio.h
index 1f1ab10..86f5409 100644
--- a/soundio/soundio.h
+++ b/soundio/soundio.h
@@ -722,10 +722,10 @@ SOUNDIO_EXPORT const char *soundio_strerror(int error);
 SOUNDIO_EXPORT const char *soundio_backend_name(enum SoundIoBackend backend);
 
 /// Returns the number of available backends.
-SOUNDIO_EXPORT int soundio_backend_count(struct SoundIo *soundio);
+SOUNDIO_EXPORT int soundio_backend_count(void);
 /// get the available backend at the specified index
 /// (0 <= index < ::soundio_backend_count)
-SOUNDIO_EXPORT enum SoundIoBackend soundio_get_backend(struct SoundIo *soundio, int index);
+SOUNDIO_EXPORT enum SoundIoBackend soundio_get_backend(int index);
 
 /// Returns whether libsoundio was compiled with backend.
 SOUNDIO_EXPORT bool soundio_have_backend(enum SoundIoBackend backend);
diff --git a/src/soundio.c b/src/soundio.c
index 32d3455..4bb5158 100644
--- a/src/soundio.c
+++ b/src/soundio.c
@@ -693,11 +693,11 @@ bool soundio_have_backend(enum SoundIoBackend backend) {
     return backend_init_fns[backend];
 }
 
-int soundio_backend_count(struct SoundIo *soundio) {
+int soundio_backend_count(void) {
     return ARRAY_LENGTH(available_backends);
 }
 
-enum SoundIoBackend soundio_get_backend(struct SoundIo *soundio, int index) {
+enum SoundIoBackend soundio_get_backend(int index) {
     return available_backends[index];
 }