diff --git a/extras/dr_mp3.h b/extras/dr_mp3.h
index 8bc5e75d..f5e58bd8 100644
--- a/extras/dr_mp3.h
+++ b/extras/dr_mp3.h
@@ -1,5 +1,5 @@
 // MP3 audio decoder. Public domain. See "unlicense" statement at the end of this file.
-// dr_mp3 - v0.3.0 - 2018-08-25
+// dr_mp3 - v0.3.1 - 2018-08-25
 //
 // David Reid - mackron@gmail.com
 //
@@ -1982,7 +1982,7 @@ int drmp3dec_decode_frame(drmp3dec *dec, const unsigned char *mp3, int mp3_bytes
             {
                 memset(scratch.grbuf[0], 0, 576*2*sizeof(float));
                 drmp3_L3_decode(dec, &scratch, scratch.gr_info + igr*info->channels, info->channels);
-                drmp3d_synth_granule(dec->qmf_state, scratch.grbuf[0], 18, info->channels, pcm, scratch.syn[0]);
+                drmp3d_synth_granule(dec->qmf_state, scratch.grbuf[0], 18, info->channels, (drmp3d_sample_t*)pcm, scratch.syn[0]);
             }
         }
         drmp3_L3_save_reservoir(dec, &scratch);
@@ -2001,7 +2001,7 @@ int drmp3dec_decode_frame(drmp3dec *dec, const unsigned char *mp3, int mp3_bytes
             {
                 i = 0;
                 drmp3_L12_apply_scf_384(sci, sci->scf + igr, scratch.grbuf[0]);
-                drmp3d_synth_granule(dec->qmf_state, scratch.grbuf[0], 12, info->channels, pcm, scratch.syn[0]);
+                drmp3d_synth_granule(dec->qmf_state, scratch.grbuf[0], 12, info->channels, (drmp3d_sample_t*)pcm, scratch.syn[0]);
                 memset(scratch.grbuf[0], 0, 576*2*sizeof(float));
                 pcm = DRMP3_OFFSET_PTR(pcm, sizeof(drmp3d_sample_t)*384*info->channels);
             }
@@ -2888,6 +2888,9 @@ void drmp3_free(void* p)
 // REVISION HISTORY
 // ===============
 //
+// v0.3.1 - 2018-08-25
+//   - Fix C++ build.
+//
 // v0.3.0 - 2018-08-25
 //   - Bring up to date with minimp3. This has a minor API change: the "pcm" parameter of drmp3dec_decode_frame() has
 //     been changed from short* to void* because it can now output both s16 and f32 samples, depending on whether or