diff --git a/lib/dns/masterdump.c b/lib/dns/masterdump.c
index 0dac5a402a..cb7c171b6a 100644
--- a/lib/dns/masterdump.c
+++ b/lib/dns/masterdump.c
@@ -332,17 +332,15 @@ totext_ctx_init(const dns_master_style_t *style, dns_totext_ctx_t *ctx) {
 	 */
 	if ((ctx->style.flags & DNS_STYLEFLAG_MULTILINE) != 0) {
 		isc_buffer_t buf;
-		isc_region_t r;
 		unsigned int col = 0;
 
 		isc_buffer_init(&buf, ctx->linebreak_buf,
 				sizeof(ctx->linebreak_buf));
 
-		isc_buffer_availableregion(&buf, &r);
-		if (r.length < 1)
+		if (isc_buffer_availablelength(&buf) < 1) {
 			return (DNS_R_TEXTTOOLONG);
-		r.base[0] = '\n';
-		isc_buffer_add(&buf, 1);
+		}
+		isc_buffer_putuint8(&buf, '\n');
 
 		if ((ctx->style.flags & DNS_STYLEFLAG_INDENT) != 0 ||
 		    (ctx->style.flags & DNS_STYLEFLAG_YAML) != 0)
@@ -356,11 +354,10 @@ totext_ctx_init(const dns_master_style_t *style, dns_totext_ctx_t *ctx) {
 		}
 
 		if ((ctx->style.flags & DNS_STYLEFLAG_COMMENTDATA) != 0) {
-			isc_buffer_availableregion(&buf, &r);
-			if (r.length < 1)
+			if (isc_buffer_availablelength(&buf) < 1) {
 				return (DNS_R_TEXTTOOLONG);
-			r.base[0] = ';';
-			isc_buffer_add(&buf, 1);
+			}
+			isc_buffer_putuint8(&buf, ';');
 		}
 
 		result = indent(&col, ctx->style.rdata_column,
@@ -377,11 +374,10 @@ totext_ctx_init(const dns_master_style_t *style, dns_totext_ctx_t *ctx) {
 		if (result != ISC_R_SUCCESS)
 			return (result);
 
-		isc_buffer_availableregion(&buf, &r);
-		if (r.length < 1)
+		if (isc_buffer_availablelength(&buf) < 1) {
 			return (DNS_R_TEXTTOOLONG);
-		r.base[0] = '\0';
-		isc_buffer_add(&buf, 1);
+		}
+		isc_buffer_putuint8(&buf, '\0');
 		ctx->linebreak = ctx->linebreak_buf;
 	} else {
 		ctx->linebreak = NULL;
@@ -671,7 +667,6 @@ rdataset_totext(dns_rdataset_t *rdataset,
 			break;
 		} else {
 			dns_rdata_t rdata = DNS_RDATA_INIT;
-			isc_region_t r;
 
 			dns_rdataset_current(rdataset, &rdata);
 
@@ -684,11 +679,10 @@ rdataset_totext(dns_rdataset_t *rdataset,
 						   ctx->linebreak,
 						   target));
 
-			isc_buffer_availableregion(target, &r);
-			if (r.length < 1)
+			if (isc_buffer_availablelength(target) < 1) {
 				return (ISC_R_NOSPACE);
-			r.base[0] = '\n';
-			isc_buffer_add(target, 1);
+			}
+			isc_buffer_putuint8(target, '\n');
 		}
 
 		first = false;
@@ -726,7 +720,6 @@ question_totext(dns_rdataset_t *rdataset,
 {
 	unsigned int column;
 	isc_result_t result;
-	isc_region_t r;
 
 	REQUIRE(DNS_RDATASET_VALID(rdataset));
 	result = dns_rdataset_first(rdataset);
@@ -775,11 +768,10 @@ question_totext(dns_rdataset_t *rdataset,
 		column += (target->used - type_start);
 	}
 
-	isc_buffer_availableregion(target, &r);
-	if (r.length < 1)
+	if (isc_buffer_availablelength(target) < 1) {
 		return (ISC_R_NOSPACE);
-	r.base[0] = '\n';
-	isc_buffer_add(target, 1);
+	}
+	isc_buffer_putuint8(target, '\n');
 
 	return (ISC_R_SUCCESS);
 }
diff --git a/lib/isc/tests/ht_test.c b/lib/isc/tests/ht_test.c
index e1abbdf84a..3ce0d96fbf 100644
--- a/lib/isc/tests/ht_test.c
+++ b/lib/isc/tests/ht_test.c
@@ -39,6 +39,7 @@ default_memalloc(void *arg, size_t size) {
 	if (size == 0U) {
 		size = 1;
 	}
+	/* cppcheck-suppress leakNoVarFunctionCall */
 	return (malloc(size));
 }
 
diff --git a/lib/isc/tests/mem_test.c b/lib/isc/tests/mem_test.c
index 11876bee7e..6a6b08cb53 100644
--- a/lib/isc/tests/mem_test.c
+++ b/lib/isc/tests/mem_test.c
@@ -54,6 +54,7 @@ default_memalloc(void *arg, size_t size) {
 	if (size == 0U) {
 		size = 1;
 	}
+	/* cppcheck-suppress leakNoVarFunctionCall */
 	return (malloc(size));
 }
 
diff --git a/lib/isc/win32/app.c b/lib/isc/win32/app.c
index 7ab0800799..9e9b508d8f 100644
--- a/lib/isc/win32/app.c
+++ b/lib/isc/win32/app.c
@@ -54,10 +54,10 @@ enum {
 };
 
 typedef struct isc__appctx {
-	isc_appctx_t		common;
-	isc_mem_t		*mctx;
-	isc_eventlist_t		on_run;
-	isc_mutex_t		lock;
+	isc_appctx_t	common;
+	isc_mem_t	*mctx;
+	isc_eventlist_t	on_run;
+	isc_mutex_t	lock;
 	bool		shutdown_requested;
 	bool		running;
 	/*
@@ -71,11 +71,11 @@ typedef struct isc__appctx {
 
 	bool		blocked;
 
-	HANDLE			hEvents[NUM_EVENTS];
+	HANDLE		hEvents[NUM_EVENTS];
 
-	isc_taskmgr_t		*taskmgr;
-	isc_socketmgr_t		*socketmgr;
-	isc_timermgr_t		*timermgr;
+	isc_taskmgr_t	*taskmgr;
+	isc_socketmgr_t	*socketmgr;
+	isc_timermgr_t	*timermgr;
 } isc__appctx_t;
 
 static isc__appctx_t isc_g_appctx;
@@ -88,7 +88,6 @@ static isc_thread_t	main_thread;
 isc_result_t
 isc_app_ctxstart(isc_appctx_t *ctx0) {
 	isc__appctx_t *ctx = (isc__appctx_t *)ctx0;
-	isc_result_t result;
 
 	REQUIRE(VALID_APPCTX(ctx));
 
diff --git a/lib/isc/win32/socket.c b/lib/isc/win32/socket.c
index a8c4f50799..bc99ec21bb 100644
--- a/lib/isc/win32/socket.c
+++ b/lib/isc/win32/socket.c
@@ -2508,7 +2508,6 @@ isc_socketmgr_create2(isc_mem_t *mctx, isc_socketmgr_t **managerp,
 		      unsigned int maxsocks, int nthreads)
 {
 	isc_socketmgr_t *manager;
-	isc_result_t result;
 
 	REQUIRE(managerp != NULL && *managerp == NULL);