diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index e6c49eebad..d18b271a58 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4638,7 +4638,7 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
     </row>
     <row>
      <entry><type>bool</type></entry>
-     <entry><type>char</type></entry>
+     <entry><type>unsigned char</type></entry>
     </row>
 
    </tbody>
diff --git a/src/backend/utils/probes.d b/src/backend/utils/probes.d
index 33ac627799..f08a49c9dd 100644
--- a/src/backend/utils/probes.d
+++ b/src/backend/utils/probes.d
@@ -9,10 +9,10 @@
 
 
 /*
- * Typedefs used in PostgreSQL.
+ * Typedefs used in PostgreSQL probes.
  *
  * NOTE: Do not use system-provided typedefs (e.g. uintptr_t, uint32_t, etc)
- * in probe definitions, as they cause compilation errors on macOS 10.5.
+ * in probe definitions, as they cause compilation errors on macOS.
  */
 #define LocalTransactionId unsigned int
 #define LWLockMode int
@@ -20,7 +20,7 @@
 #define BlockNumber unsigned int
 #define Oid unsigned int
 #define ForkNumber int
-#define bool char
+#define bool unsigned char
 
 provider postgresql {