diff --git a/src/lib/blit.c b/src/lib/blit.c
index d0f98e478..d57f6b579 100644
--- a/src/lib/blit.c
+++ b/src/lib/blit.c
@@ -844,7 +844,7 @@ int ncblit_bgrx(const void* data, int linesize, const struct ncvisual_options* v
 
 int ncblit_rgba(const void* data, int linesize, const struct ncvisual_options* vopts){
   if(vopts->flags > NCVISUAL_OPTION_BLEND){
-    fprintf(stderr, "Warning: unknown ncvisual options %016lx\n", vopts->flags);
+    fprintf(stderr, "Warning: unknown ncvisual options %016jx\n", (uintmax_t)vopts->flags);
   }
   if(linesize <= 0 || (size_t)linesize < vopts->lenx * sizeof(uint32_t)){
     return -1;
diff --git a/src/lib/fd.c b/src/lib/fd.c
index 9fd92598f..a728acd68 100644
--- a/src/lib/fd.c
+++ b/src/lib/fd.c
@@ -101,7 +101,7 @@ ncfdplane_create_internal(ncplane* n, const ncfdplane_options* opts, int fd,
                           ncfdplane_callback cbfxn, ncfdplane_done_cb donecbfxn,
                           bool thread){
   if(opts->flags > 0){
-    logwarn(ncplane_notcurses(n), "Provided unsupported flags %016lx\n", opts->flags);
+    logwarn(ncplane_notcurses(n), "Provided unsupported flags %016jx\n", (uintmax_t)opts->flags);
   }
   ncfdplane* ret = malloc(sizeof(*ret));
   if(ret == NULL){
@@ -302,7 +302,7 @@ ncsubproc* ncsubproc_createv(ncplane* n, const ncsubproc_options* opts,
     return NULL;
   }
   if(opts->flags > 0){
-    logwarn(ncplane_notcurses(n), "Provided unsupported flags %016lx\n", opts->flags);
+    logwarn(ncplane_notcurses(n), "Provided unsupported flags %016jx\n", (uintmax_t)opts->flags);
   }
   int fd = -1;
   ncsubproc* ret = malloc(sizeof(*ret));
@@ -337,7 +337,7 @@ ncsubproc* ncsubproc_createvp(ncplane* n, const ncsubproc_options* opts,
     return NULL;
   }
   if(opts->flags > 0){
-    logwarn(ncplane_notcurses(n), "Provided unsupported flags %016lx\n", opts->flags);
+    logwarn(ncplane_notcurses(n), "Provided unsupported flags %016jx\n", (uintmax_t)opts->flags);
   }
   int fd = -1;
   ncsubproc* ret = malloc(sizeof(*ret));
@@ -372,7 +372,7 @@ ncsubproc* ncsubproc_createvpe(ncplane* n, const ncsubproc_options* opts,
     return NULL;
   }
   if(opts->flags > 0){
-    logwarn(ncplane_notcurses(n), "Provided unsupported flags %016lx\n", opts->flags);
+    logwarn(ncplane_notcurses(n), "Provided unsupported flags %016jx\n", (uintmax_t)opts->flags);
   }
   int fd = -1;
   ncsubproc* ret = malloc(sizeof(*ret));
diff --git a/src/lib/linux.c b/src/lib/linux.c
index 0b00b8cfc..89eb167cb 100644
--- a/src/lib/linux.c
+++ b/src/lib/linux.c
@@ -458,11 +458,11 @@ program_block_drawing_chars(const notcurses* nc, struct consolefontdesc* cfd,
         }
       }
       if(candidate == 0){
-        logwarn(nc, "Ran out of replaceable glyphs for U+%04x\n", shimmers[s].w);
+        logwarn(nc, "Ran out of replaceable glyphs for U+%04lx\n", (long)shimmers[s].w);
         return -1;
       }
       if(shimmers[s].glyphfxn(cfd, candidate)){
-        logwarn(nc, "Error replacing glyph for U+%04x at %u\n", shimmers[s].w, candidate);
+        logwarn(nc, "Error replacing glyph for U+%04lx at %u\n", (long)shimmers[s].w, candidate);
         return -1;
       }
       if(add_to_map(nc, map, shimmers[s].w, candidate)){
diff --git a/src/lib/menu.c b/src/lib/menu.c
index 1cf3d9b31..6d25e2cd3 100644
--- a/src/lib/menu.c
+++ b/src/lib/menu.c
@@ -306,7 +306,7 @@ ncmenu* ncmenu_create(ncplane* n, const ncmenu_options* opts){
     return NULL;
   }
   if(opts->flags > NCMENU_OPTION_HIDING){
-    logwarn(ncplane_notcurses(n), "Provided unsupported flags %016lx\n", opts->flags);
+    logwarn(ncplane_notcurses(n), "Provided unsupported flags %016jx\n", (uintmax_t)opts->flags);
   }
   int totalheight = 1;
   int totalwidth = 2; // start with two-character margin on the left
diff --git a/src/lib/notcurses.c b/src/lib/notcurses.c
index 05f2b971d..1487f6e3a 100644
--- a/src/lib/notcurses.c
+++ b/src/lib/notcurses.c
@@ -337,7 +337,7 @@ make_ncpile(notcurses* nc, ncplane* n){
 ncplane* ncplane_new_internal(notcurses* nc, ncplane* n,
                               const ncplane_options* nopts){
   if(nopts->flags > NCPLANE_OPTION_HORALIGNED){
-    logwarn(nc, "Provided unsupported flags %016lx\n", nopts->flags);
+    logwarn(nc, "Provided unsupported flags %016jx\n", (uintmax_t)nopts->flags);
   }
   if(nopts->rows <= 0 || nopts->cols <= 0){
     logerror(nc, "Won't create denormalized plane (r=%d, c=%d)\n",
@@ -985,7 +985,7 @@ notcurses* notcurses_init(const notcurses_options* opts, FILE* outfp){
     return NULL;
   }
   if(opts->flags >= (NCOPTION_NO_FONT_CHANGES << 1u)){
-    fprintf(stderr, "Warning: unknown Notcurses options %016lx\n", opts->flags);
+    fprintf(stderr, "Warning: unknown Notcurses options %016jx\n", (uintmax_t)opts->flags);
   }
   notcurses* ret = malloc(sizeof(*ret));
   if(ret == NULL){
diff --git a/src/lib/plot.h b/src/lib/plot.h
index 729d9206f..9523695b2 100644
--- a/src/lib/plot.h
+++ b/src/lib/plot.h
@@ -21,7 +21,7 @@ class ncppplot {
      opts = &zeroed;
    }
    if(opts->flags > NCPLOT_OPTION_DETECTMAXONLY){
-     logwarn(ncplane_notcurses(n), "Provided unsupported flags %016lx\n", opts->flags);
+     logwarn(ncplane_notcurses(n), "Provided unsupported flags %016jx\n", (uintmax_t)opts->flags);
    }
    //struct notcurses* nc = n->nc;
    // if miny == maxy (enabling domain detection), they both must be equal to 0
diff --git a/src/lib/reader.c b/src/lib/reader.c
index 836857854..a2c61bb7e 100644
--- a/src/lib/reader.c
+++ b/src/lib/reader.c
@@ -6,7 +6,7 @@ ncreader* ncreader_create(ncplane* n, const ncreader_options* opts){
     opts = &zeroed;
   }
   if(opts->flags > NCREADER_OPTION_CURSOR){
-    logwarn(ncplane_notcurses(n), "Provided unsupported flags %016lx\n", opts->flags);
+    logwarn(ncplane_notcurses(n), "Provided unsupported flags %016jx\n", (uintmax_t)opts->flags);
   }
   ncreader* nr = malloc(sizeof(*nr));
   if(nr == NULL){
diff --git a/src/lib/reel.c b/src/lib/reel.c
index d3003b67e..7f2b18b0c 100644
--- a/src/lib/reel.c
+++ b/src/lib/reel.c
@@ -718,7 +718,7 @@ validate_ncreel_opts(ncplane* n, const ncreel_options* ropts){
     return false;
   }
   if(ropts->flags > NCREEL_OPTION_CIRCULAR){
-    logwarn(ncplane_notcurses(n), "Provided unsupported flags %016lx\n", ropts->flags);
+    logwarn(ncplane_notcurses(n), "Provided unsupported flags %016jx\n", (uintmax_t)ropts->flags);
   }
   if(ropts->flags & NCREEL_OPTION_CIRCULAR){
     if(!(ropts->flags & NCREEL_OPTION_INFINITESCROLL)){
diff --git a/src/lib/selector.c b/src/lib/selector.c
index fda7c3591..9a2c98857 100644
--- a/src/lib/selector.c
+++ b/src/lib/selector.c
@@ -833,7 +833,7 @@ ncmultiselector* ncmultiselector_create(ncplane* n, const ncmultiselector_option
     opts = &zeroed;
   }
   if(opts->flags > 0){
-    logwarn(ncplane_notcurses(n), "Provided unsupported flags %016lx\n", opts->flags);
+    logwarn(ncplane_notcurses(n), "Provided unsupported flags %016jx\n", (uintmax_t)opts->flags);
   }
   unsigned itemcount = 0;
   if(opts->items){
diff --git a/src/lib/visual.cpp b/src/lib/visual.cpp
index edd35fe2e..02cfd5e94 100644
--- a/src/lib/visual.cpp
+++ b/src/lib/visual.cpp
@@ -364,7 +364,7 @@ auto ncvisual_from_bgra(const void* bgra, int rows, int rowstride,
 auto ncvisual_render(notcurses* nc, ncvisual* ncv,
                      const struct ncvisual_options* vopts) -> ncplane* {
   if(vopts && vopts->flags > NCVISUAL_OPTION_BLEND){
-    fprintf(stderr, "Warning: unknown ncvisual options %016lx\n", vopts->flags);
+    fprintf(stderr, "Warning: unknown ncvisual options %016jx\n", (uintmax_t)vopts->flags);
   }
   int lenx = vopts ? vopts->lenx : 0;
   int leny = vopts ? vopts->leny : 0;
diff --git a/src/poc/wcwidth.c b/src/poc/wcwidth.c
index df4bbcbcc..b2de96378 100644
--- a/src/poc/wcwidth.c
+++ b/src/poc/wcwidth.c
@@ -21,7 +21,7 @@ int main(int argc, char **argv){
           return EXIT_FAILURE;
         }
         int width = wcwidth(w);
-        printf("w(0x%05x): %d %lc\n", w, width, w);
+        printf("w(0x%05lx): %d %lc\n", (long)w, width, w);
         arg += conv;
       }
     }