diff --git a/include/mimalloc.h b/include/mimalloc.h
index 6d9eb4fc..ec6dabc6 100644
--- a/include/mimalloc.h
+++ b/include/mimalloc.h
@@ -276,7 +276,7 @@ mi_decl_export int mi_reserve_huge_os_pages_at(size_t pages, int numa_node, size
 mi_decl_export int  mi_reserve_os_memory(size_t size, bool commit, bool allow_large) mi_attr_noexcept;
 mi_decl_export bool mi_manage_os_memory(void* start, size_t size, bool is_committed, bool is_large, bool is_zero, int numa_node) mi_attr_noexcept;
 
-mi_decl_export void mi_debug_show_arenas(bool show_inuse) mi_attr_noexcept;
+mi_decl_export void mi_debug_show_arenas(void) mi_attr_noexcept;
 
 // Experimental: heaps associated with specific memory arena's
 typedef int mi_arena_id_t;
diff --git a/include/mimalloc/internal.h b/include/mimalloc/internal.h
index 4a798d0a..8d26de47 100644
--- a/include/mimalloc/internal.h
+++ b/include/mimalloc/internal.h
@@ -64,8 +64,8 @@ terms of the MIT license. A copy of the license can be found in the file
 
 // "libc.c"
 #include    <stdarg.h>
-void        _mi_vsnprintf(char* buf, size_t bufsize, const char* fmt, va_list args);
-void        _mi_snprintf(char* buf, size_t buflen, const char* fmt, ...);
+int         _mi_vsnprintf(char* buf, size_t bufsize, const char* fmt, va_list args);
+int         _mi_snprintf(char* buf, size_t buflen, const char* fmt, ...);
 char        _mi_toupper(char c);
 int         _mi_strnicmp(const char* s, const char* t, size_t n);
 void        _mi_strlcpy(char* dest, const char* src, size_t dest_size);
diff --git a/src/arena.c b/src/arena.c
index ce08d601..a97299ee 100644
--- a/src/arena.c
+++ b/src/arena.c
@@ -923,7 +923,8 @@ static size_t mi_debug_show_bitmap(const char* prefix, const char* header, size_
   return inuse_count;
 }
 
-void mi_debug_show_arenas(bool show_inuse) mi_attr_noexcept {
+void mi_debug_show_arenas(void) mi_attr_noexcept {
+  const bool show_inuse = true;
   size_t max_arenas = mi_atomic_load_relaxed(&mi_arena_count);
   size_t inuse_total = 0;
   //size_t abandoned_total = 0;
diff --git a/src/libc.c b/src/libc.c
index ce541f1b..1bd97aa3 100644
--- a/src/libc.c
+++ b/src/libc.c
@@ -7,7 +7,7 @@ terms of the MIT license. A copy of the license can be found in the file
 
 // --------------------------------------------------------
 // This module defines various std libc functions to reduce
-// the dependency on libc, and also prevent errors caused 
+// the dependency on libc, and also prevent errors caused
 // by some libc implementations when called before `main`
 // executes (due to malloc redirection)
 // --------------------------------------------------------
@@ -83,7 +83,7 @@ bool _mi_getenv(const char* name, char* result, size_t result_size) {
 // Define our own limited `_mi_vsnprintf` and `_mi_snprintf`
 // This is mostly to avoid calling these when libc is not yet
 // initialized (and to reduce dependencies)
-// 
+//
 // format:      d i, p x u, s
 // prec:        z l ll L
 // width:       10
@@ -130,7 +130,7 @@ static void mi_out_alignright(char fill, char* start, size_t len, size_t extra,
 }
 
 
-static void mi_out_num(uintmax_t x, size_t base, char prefix, char** out, char* end) 
+static void mi_out_num(uintmax_t x, size_t base, char prefix, char** out, char* end)
 {
   if (x == 0 || base == 0 || base > 16) {
     if (prefix != 0) { mi_outc(prefix, out, end); }
@@ -144,8 +144,8 @@ static void mi_out_num(uintmax_t x, size_t base, char prefix, char** out, char*
       mi_outc((digit <= 9 ? '0' + digit : 'A' + digit - 10),out,end);
       x = x / base;
     }
-    if (prefix != 0) { 
-      mi_outc(prefix, out, end); 
+    if (prefix != 0) {
+      mi_outc(prefix, out, end);
     }
     size_t len = *out - start;
     // and reverse in-place
@@ -160,8 +160,8 @@ static void mi_out_num(uintmax_t x, size_t base, char prefix, char** out, char*
 
 #define MI_NEXTC()  c = *in; if (c==0) break; in++;
 
-void _mi_vsnprintf(char* buf, size_t bufsize, const char* fmt, va_list args) {
-  if (buf == NULL || bufsize == 0 || fmt == NULL) return;
+int _mi_vsnprintf(char* buf, size_t bufsize, const char* fmt, va_list args) {
+  if (buf == NULL || bufsize == 0 || fmt == NULL) return 0;
   buf[bufsize - 1] = 0;
   char* const end = buf + (bufsize - 1);
   const char* in = fmt;
@@ -181,7 +181,7 @@ void _mi_vsnprintf(char* buf, size_t bufsize, const char* fmt, va_list args) {
       size_t width = 0;
       char   numtype = 'd';
       char   numplus = 0;
-      bool   alignright = true; 
+      bool   alignright = true;
       if (c == '+' || c == ' ') { numplus = c; MI_NEXTC(); }
       if (c == '-') { alignright = false; MI_NEXTC(); }
       if (c == '0') { fill = '0'; MI_NEXTC(); }
@@ -191,7 +191,7 @@ void _mi_vsnprintf(char* buf, size_t bufsize, const char* fmt, va_list args) {
           width = (10 * width) + (c - '0'); MI_NEXTC();
         }
         if (c == 0) break;  // extra check due to while
-      }      
+      }
       if (c == 'z' || c == 't' || c == 'L') { numtype = c; MI_NEXTC(); }
       else if (c == 'l') {
         numtype = c; MI_NEXTC();
@@ -265,11 +265,13 @@ void _mi_vsnprintf(char* buf, size_t bufsize, const char* fmt, va_list args) {
   }
   mi_assert_internal(out <= end);
   *out = 0;
+  return (int)(out - buf);
 }
 
-void _mi_snprintf(char* buf, size_t buflen, const char* fmt, ...) {
+int _mi_snprintf(char* buf, size_t buflen, const char* fmt, ...) {
   va_list args;
   va_start(args, fmt);
-  _mi_vsnprintf(buf, buflen, fmt, args);
+  const int written = _mi_vsnprintf(buf, buflen, fmt, args);
   va_end(args);
+  return written;
 }
diff --git a/src/page.c b/src/page.c
index e1c07a93..6d0d6db7 100644
--- a/src/page.c
+++ b/src/page.c
@@ -411,7 +411,7 @@ void _mi_page_force_abandon(mi_page_t* page) {
 
   // ensure this page is no longer in the heap delayed free list
   _mi_heap_delayed_free_all(heap);
-  // We can still access the page meta-info even if it is freed as we ensure 
+  // We can still access the page meta-info even if it is freed as we ensure
   // in `mi_segment_force_abandon` that the segment is not freed (yet)
   if (page->capacity == 0) return; // it may have been freed now
 
@@ -990,14 +990,20 @@ void* _mi_malloc_generic(mi_heap_t* heap, size_t size, bool zero, size_t huge_al
   mi_assert_internal(mi_page_block_size(page) >= size);
 
   // and try again, this time succeeding! (i.e. this should never recurse through _mi_page_malloc)
+  void* p;
   if mi_unlikely(zero && mi_page_is_huge(page)) {
     // note: we cannot call _mi_page_malloc with zeroing for huge blocks; we zero it afterwards in that case.
-    void* p = _mi_page_malloc(heap, page, size);
+    p = _mi_page_malloc(heap, page, size);
     mi_assert_internal(p != NULL);
     _mi_memzero_aligned(p, mi_page_usable_block_size(page));
-    return p;
   }
   else {
-    return _mi_page_malloc_zero(heap, page, size, zero);
+    p = _mi_page_malloc_zero(heap, page, size, zero);
+    mi_assert_internal(p != NULL);
   }
+  // move singleton pages to the full queue
+  if (page->reserved == page->used) {
+    mi_page_to_full(page, mi_page_queue_of(page));
+  }
+  return p;
 }
diff --git a/test/test-stress.c b/test/test-stress.c
index 8c5fca9c..dc7f9cb0 100644
--- a/test/test-stress.c
+++ b/test/test-stress.c
@@ -316,7 +316,7 @@ int main(int argc, char** argv) {
 
 #ifndef USE_STD_MALLOC
   #ifndef NDEBUG
-  mi_debug_show_arenas(true);
+  mi_debug_show_arenas();
   mi_collect(true);
   #endif  
 #endif