diff --git a/src/demo/witherworm.c b/src/demo/witherworm.c
index 8a8cb1eed..aab4f9ba2 100644
--- a/src/demo/witherworm.c
+++ b/src/demo/witherworm.c
@@ -483,7 +483,9 @@ int witherworm_demo(struct notcurses* nc){
             break;
           }
           wchar_t wcs;
-          int eaten = mbtowc(&wcs, &(*s)[idx], MB_CUR_MAX + 1);
+          mbstate_t mbstate;
+          memset(&mbstate, 0, sizeof(mbstate));
+          int eaten = mbrtowc(&wcs, &(*s)[idx], MB_CUR_MAX + 1, &mbstate);
           if(eaten < 0){
             return -1;
           }
diff --git a/src/lib/egcpool.h b/src/lib/egcpool.h
index b77b813b9..21969a3a7 100644
--- a/src/lib/egcpool.h
+++ b/src/lib/egcpool.h
@@ -59,7 +59,7 @@ egcpool_grow(egcpool* pool, size_t len){
 }
 
 // Eat an EGC from the UTF-8 string input. This consists of extracting a
-// multibyte via mbtowc, then continuing to extract any which have zero
+// multibyte via mbrtowc, then continuing to extract any which have zero
 // width until hitting another spacing character or a NUL terminator. Writes
 // the number of columns occupied to '*colcount'. Returns the number of bytes
 // consumed, not including any NUL terminator. Note that neither the number
@@ -193,9 +193,11 @@ egcpool_check_validity(const egcpool* pool, int offset){
     fprintf(stderr, "Bad offset 0x%06x: empty\n", offset);
     return false;
   }
+  mbstate_t mbstate;
+  memset(&mbstate, 0, sizeof(mbstate));
   do{
     wchar_t wcs;
-    int r = mbtowc(&wcs, egc, strlen(egc));
+    int r = mbrtowc(&wcs, egc, strlen(egc), &mbstate);
     if(r < 0){
       fprintf(stderr, "Invalid UTF8 at offset 0x%06x, len %zu [%s]\n",
               offset, strlen(egc), strerror(errno));
diff --git a/src/lib/input.c b/src/lib/input.c
index a59c0627c..e247b0b61 100644
--- a/src/lib/input.c
+++ b/src/lib/input.c
@@ -251,8 +251,12 @@ handle_getc(notcurses* nc, int kpress, ncinput* ni){
   }
   cpoint[cpointlen] = '\0';
   wchar_t w;
+  mbstate_t mbstate;
+  memset(&mbstate, 0, sizeof(mbstate));
   // FIXME how the hell does this work with 16-bit wchar_t?
-  if(mbtowc(&w, cpoint, cpointlen) < 0){
+  size_t r;
+  if((r = mbrtowc(&w, cpoint, cpointlen, &mbstate)) == (size_t)-1 ||
+      r == (size_t)-2){
     return (wchar_t)-1;
   }
   return w;