diff --git a/src/sound_beos.cpp b/src/sound_beos.cpp
index f81f8cc..587aea0 100644
--- a/src/sound_beos.cpp
+++ b/src/sound_beos.cpp
@@ -121,7 +121,7 @@ static int read_buffer(unsigned char *data, int len)
 	return len;
 }
 
-void render_proc(void *theCookie, void *buffer, size_t req, 
+static void render_proc(void *theCookie, void *buffer, size_t req, 
 				const media_raw_audio_format &format)
 {
 	size_t amt;
diff --git a/src/sound_coreaudio.c b/src/sound_coreaudio.c
index 3ef640f..c176561 100644
--- a/src/sound_coreaudio.c
+++ b/src/sound_coreaudio.c
@@ -103,7 +103,7 @@ static int read_buffer(unsigned char *data, int len)
 	return len;
 }
 
-OSStatus render_proc(void *inRefCon,
+static OSStatus render_proc(void *inRefCon,
 		AudioUnitRenderActionFlags *inActionFlags,
 		const AudioTimeStamp *inTimeStamp, UInt32 inBusNumber,
 		UInt32 inNumFrames, AudioBufferList *ioData)