diff --git a/libc/lib_internal.h b/libc/lib_internal.h
index bf73b72a4d..1b7f232c52 100644
--- a/libc/lib_internal.h
+++ b/libc/lib_internal.h
@@ -186,7 +186,7 @@ ssize_t lib_fread(FAR void *ptr, size_t count, FAR FILE *stream);
 
 /* Defined in lib_libfgets.c */
 
-FAR char *lib_fgets(FAR char *buf, int buflen, FILE *stream,
+FAR char *lib_fgets(FAR char *buf, size_t buflen, FILE *stream,
                     bool keepnl, bool consume);
 
 /* Defined in lib_libfflush.c */
diff --git a/libc/stdio/lib_fgets.c b/libc/stdio/lib_fgets.c
index 3aff54db9e..47f35597c1 100644
--- a/libc/stdio/lib_fgets.c
+++ b/libc/stdio/lib_fgets.c
@@ -69,7 +69,17 @@
 
 char *fgets(FAR char *buf, int buflen, FILE *stream)
 {
+  /* Handle negative buffer size */
+
+  if (buflen < 0)
+    {
+      return NULL;
+    }
+
   /* Let lib_fgets() do the heavy lifting */
 
-  return lib_fgets(buf, buflen, stream, true, false);
+  else
+    {
+      return lib_fgets(buf, (size_t)buflen, stream, true, false);
+    }
 }
diff --git a/libc/stdio/lib_gets.c b/libc/stdio/lib_gets.c
index e9e36987ba..d15c8bd08a 100644
--- a/libc/stdio/lib_gets.c
+++ b/libc/stdio/lib_gets.c
@@ -73,5 +73,5 @@ FAR char *gets(FAR char *s)
 {
   /* Let lib_fgets() do the heavy lifting */
 
-  return lib_fgets(s, RSIZE_MAX, stdin, false, false);
+  return lib_fgets(s, (size_t)INT_MAX, stdin, false, false);
 }
diff --git a/libc/stdio/lib_gets_s.c b/libc/stdio/lib_gets_s.c
index 3f9ecc0cb2..54f8891f91 100644
--- a/libc/stdio/lib_gets_s.c
+++ b/libc/stdio/lib_gets_s.c
@@ -92,5 +92,5 @@ FAR char *gets_s(FAR char *s, rsize_t n)
 
   /* Then let lib_fgets() do the heavy lifting */
 
-  return lib_fgets(s, n, stdin, false, true);
+  return lib_fgets(s, (size_t)n, stdin, false, true);
 }
diff --git a/libc/stdio/lib_libfgets.c b/libc/stdio/lib_libfgets.c
index 6a8cdeb448..bc41d94e51 100644
--- a/libc/stdio/lib_libfgets.c
+++ b/libc/stdio/lib_libfgets.c
@@ -139,7 +139,7 @@ static void consume_eol(FILE *stream, bool consume)
  *
  **************************************************************************/
 
-FAR char *lib_fgets(FAR char *buf, int buflen, FILE *stream,
+FAR char *lib_fgets(FAR char *buf, size_t buflen, FILE *stream,
                     bool keepnl, bool consume)
 {
   int nch = 0;