diff --git a/bin/named/main.c b/bin/named/main.c
index 4fdfa98fa3..c496bfb587 100644
--- a/bin/named/main.c
+++ b/bin/named/main.c
@@ -240,12 +240,12 @@ assertion_failed(const char *file, int line, isc_assertiontype_t type,
 }
 
 noreturn static void
-library_fatal_error(const char *file, int line, const char *format,
-		    va_list args) ISC_FORMAT_PRINTF(3, 0);
+library_fatal_error(const char *file, int line, const char *func,
+		    const char *format, va_list args) ISC_FORMAT_PRINTF(3, 0);
 
 static void
-library_fatal_error(const char *file, int line, const char *format,
-		    va_list args) {
+library_fatal_error(const char *file, int line, const char *func,
+		    const char *format, va_list args) {
 	/*
 	 * Handle isc_error_fatal() calls from our libraries.
 	 */
@@ -259,7 +259,7 @@ library_fatal_error(const char *file, int line, const char *format,
 
 		isc_log_write(named_g_lctx, NAMED_LOGCATEGORY_GENERAL,
 			      NAMED_LOGMODULE_MAIN, ISC_LOG_CRITICAL,
-			      "%s:%d: fatal error:", file, line);
+			      "%s:%d:%s(): fatal error: ", file, line, func);
 		isc_log_vwrite(named_g_lctx, NAMED_LOGCATEGORY_GENERAL,
 			       NAMED_LOGMODULE_MAIN, ISC_LOG_CRITICAL, format,
 			       args);
@@ -267,7 +267,7 @@ library_fatal_error(const char *file, int line, const char *format,
 			      NAMED_LOGMODULE_MAIN, ISC_LOG_CRITICAL,
 			      "exiting (due to fatal error in library)");
 	} else {
-		fprintf(stderr, "%s:%d: fatal error: ", file, line);
+		fprintf(stderr, "%s:%d:%s(): fatal error: ", file, line, func);
 		vfprintf(stderr, format, args);
 		fprintf(stderr, "\n");
 		fflush(stderr);
@@ -280,12 +280,13 @@ library_fatal_error(const char *file, int line, const char *format,
 }
 
 static void
-library_unexpected_error(const char *file, int line, const char *format,
-			 va_list args) ISC_FORMAT_PRINTF(3, 0);
+library_unexpected_error(const char *file, int line, const char *func,
+			 const char *format, va_list args)
+	ISC_FORMAT_PRINTF(3, 0);
 
 static void
-library_unexpected_error(const char *file, int line, const char *format,
-			 va_list args) {
+library_unexpected_error(const char *file, int line, const char *func,
+			 const char *format, va_list args) {
 	/*
 	 * Handle isc_error_unexpected() calls from our libraries.
 	 */
@@ -293,12 +294,13 @@ library_unexpected_error(const char *file, int line, const char *format,
 	if (named_g_lctx != NULL) {
 		isc_log_write(named_g_lctx, NAMED_LOGCATEGORY_GENERAL,
 			      NAMED_LOGMODULE_MAIN, ISC_LOG_ERROR,
-			      "%s:%d: unexpected error:", file, line);
+			      "%s:%d:%s(): unexpected error: ", file, line,
+			      func);
 		isc_log_vwrite(named_g_lctx, NAMED_LOGCATEGORY_GENERAL,
 			       NAMED_LOGMODULE_MAIN, ISC_LOG_ERROR, format,
 			       args);
 	} else {
-		fprintf(stderr, "%s:%d: fatal error: ", file, line);
+		fprintf(stderr, "%s:%d:%s(): fatal error: ", file, line, func);
 		vfprintf(stderr, format, args);
 		fprintf(stderr, "\n");
 		fflush(stderr);
diff --git a/bin/tests/system/dyndb/driver/db.c b/bin/tests/system/dyndb/driver/db.c
index 05485bd631..a2bdb6916b 100644
--- a/bin/tests/system/dyndb/driver/db.c
+++ b/bin/tests/system/dyndb/driver/db.c
@@ -133,7 +133,7 @@ beginload(dns_db_t *db, dns_rdatacallbacks_t *callbacks) {
 	UNUSED(db);
 	UNUSED(callbacks);
 
-	fatal_error("current implementation should never call beginload()");
+	FATAL_ERROR("current implementation should never call beginload()");
 
 	/* Not reached */
 	return (ISC_R_SUCCESS);
@@ -149,7 +149,7 @@ endload(dns_db_t *db, dns_rdatacallbacks_t *callbacks) {
 	UNUSED(db);
 	UNUSED(callbacks);
 
-	fatal_error("current implementation should never call endload()");
+	FATAL_ERROR("current implementation should never call endload()");
 
 	/* Not reached */
 	return (ISC_R_SUCCESS);
@@ -163,7 +163,7 @@ dump(dns_db_t *db, dns_dbversion_t *version, const char *filename,
 	UNUSED(filename);
 	UNUSED(masterformat);
 
-	fatal_error("current implementation should never call dump()");
+	FATAL_ERROR("current implementation should never call dump()");
 
 	/* Not reached */
 	return (ISC_R_SUCCESS);
diff --git a/bin/tests/system/dyndb/driver/log.h b/bin/tests/system/dyndb/driver/log.h
index 2cb968bf81..375db2b46a 100644
--- a/bin/tests/system/dyndb/driver/log.h
+++ b/bin/tests/system/dyndb/driver/log.h
@@ -34,8 +34,6 @@
 
 #include <dns/log.h>
 
-#define fatal_error(...) isc_error_fatal(__FILE__, __LINE__, __VA_ARGS__)
-
 #define log_error_r(fmt, ...) \
 	log_error(fmt ": %s", ##__VA_ARGS__, isc_result_totext(result))
 
diff --git a/bin/tests/system/dyndb/driver/syncptr.c b/bin/tests/system/dyndb/driver/syncptr.c
index 81d98e5d43..5124df32b4 100644
--- a/bin/tests/system/dyndb/driver/syncptr.c
+++ b/bin/tests/system/dyndb/driver/syncptr.c
@@ -157,7 +157,7 @@ syncptr_find_zone(sample_instance_t *inst, dns_rdata_t *rdata, dns_name_t *name,
 		break;
 
 	default:
-		fatal_error("unsupported address type 0x%x", rdata->type);
+		FATAL_ERROR("unsupported address type 0x%x", rdata->type);
 		break;
 	}
 
diff --git a/lib/isc/error.c b/lib/isc/error.c
index 336be8432e..051a6c48aa 100644
--- a/lib/isc/error.c
+++ b/lib/isc/error.c
@@ -21,12 +21,12 @@
 
 /*% Default unexpected callback. */
 static void
-default_unexpected_callback(const char *, int, const char *, va_list)
-	ISC_FORMAT_PRINTF(3, 0);
+default_unexpected_callback(const char *, int, const char *, const char *,
+			    va_list) ISC_FORMAT_PRINTF(4, 0);
 
 /*% Default fatal callback. */
 static void
-default_fatal_callback(const char *, int, const char *, va_list)
+default_fatal_callback(const char *, int, const char *, const char *, va_list)
 	ISC_FORMAT_PRINTF(3, 0);
 
 /*% unexpected_callback */
@@ -52,42 +52,39 @@ isc_error_setfatal(isc_errorcallback_t cb) {
 }
 
 void
-isc_error_unexpected(const char *file, int line, const char *format, ...) {
+isc_error_unexpected(const char *file, int line, const char *func,
+		     const char *format, ...) {
 	va_list args;
 
 	va_start(args, format);
-	(unexpected_callback)(file, line, format, args);
+	(unexpected_callback)(file, line, func, format, args);
 	va_end(args);
 }
 
 void
-isc_error_fatal(const char *file, int line, const char *format, ...) {
+isc_error_fatal(const char *file, int line, const char *func,
+		const char *format, ...) {
 	va_list args;
 
 	va_start(args, format);
-	(fatal_callback)(file, line, format, args);
+	(fatal_callback)(file, line, func, format, args);
 	va_end(args);
 	abort();
 }
 
-void
-isc_error_runtimecheck(const char *file, int line, const char *expression) {
-	isc_error_fatal(file, line, "RUNTIME_CHECK(%s) failed", expression);
-}
-
 static void
-default_unexpected_callback(const char *file, int line, const char *format,
-			    va_list args) {
-	fprintf(stderr, "%s:%d: ", file, line);
+default_unexpected_callback(const char *file, int line, const char *func,
+			    const char *format, va_list args) {
+	fprintf(stderr, "%s:%d:%s(): ", file, line, func);
 	vfprintf(stderr, format, args);
 	fprintf(stderr, "\n");
 	fflush(stderr);
 }
 
 static void
-default_fatal_callback(const char *file, int line, const char *format,
-		       va_list args) {
-	fprintf(stderr, "%s:%d: fatal error: ", file, line);
+default_fatal_callback(const char *file, int line, const char *func,
+		       const char *format, va_list args) {
+	fprintf(stderr, "%s:%d:%s(): fatal error: ", file, line, func);
 	vfprintf(stderr, format, args);
 	fprintf(stderr, "\n");
 	fflush(stderr);
diff --git a/lib/isc/include/isc/error.h b/lib/isc/include/isc/error.h
index 96552bcb78..f4f668203f 100644
--- a/lib/isc/include/isc/error.h
+++ b/lib/isc/include/isc/error.h
@@ -23,7 +23,8 @@
 
 ISC_LANG_BEGINDECLS
 
-typedef void (*isc_errorcallback_t)(const char *, int, const char *, va_list);
+typedef void (*isc_errorcallback_t)(const char *, int, const char *,
+				    const char *, va_list);
 
 /*% set unexpected error */
 void isc_error_setunexpected(isc_errorcallback_t);
@@ -33,15 +34,12 @@ void isc_error_setfatal(isc_errorcallback_t);
 
 /*% unexpected error */
 void
-isc_error_unexpected(const char *, int, const char *, ...)
-	ISC_FORMAT_PRINTF(3, 4);
+isc_error_unexpected(const char *, int, const char *, const char *, ...)
+	ISC_FORMAT_PRINTF(4, 5);
 
 /*% fatal error */
 noreturn void
-isc_error_fatal(const char *, int, const char *, ...) ISC_FORMAT_PRINTF(3, 4);
-
-/*% runtimecheck error */
-noreturn void
-isc_error_runtimecheck(const char *, int, const char *);
+isc_error_fatal(const char *, int, const char *, const char *, ...)
+	ISC_FORMAT_PRINTF(4, 5);
 
 ISC_LANG_ENDDECLS
diff --git a/lib/isc/include/isc/util.h b/lib/isc/include/isc/util.h
index 66b82eb1ad..6b8e581450 100644
--- a/lib/isc/include/isc/util.h
+++ b/lib/isc/include/isc/util.h
@@ -313,16 +313,17 @@ mock_assert(const int result, const char *const expression,
 #include <isc/strerr.h> /* for ISC_STRERRORSIZE */
 
 #define UNEXPECTED_ERROR(...) \
-	isc_error_unexpected(__FILE__, __LINE__, __VA_ARGS__)
+	isc_error_unexpected(__FILE__, __LINE__, __func__, __VA_ARGS__)
 
-#define FATAL_ERROR(...) isc_error_fatal(__FILE__, __LINE__, __VA_ARGS__)
+#define FATAL_ERROR(...) \
+	isc_error_fatal(__FILE__, __LINE__, __func__, __VA_ARGS__)
 
-#define REPORT_SYSERROR(report, err, fmt, ...)                             \
-	{                                                                  \
-		char _strerr[ISC_STRERRORSIZE];                            \
-		strerror_r(err, _strerr, sizeof(_strerr));                 \
-		report(__FILE__, __LINE__, fmt ": %s (%d)", ##__VA_ARGS__, \
-		       _strerr, err);                                      \
+#define REPORT_SYSERROR(report, err, fmt, ...)                        \
+	{                                                             \
+		char strerr[ISC_STRERRORSIZE];                        \
+		strerror_r(err, strerr, sizeof(strerr));              \
+		report(__FILE__, __LINE__, __func__, fmt ": %s (%d)", \
+		       ##__VA_ARGS__, strerr, err);                   \
 	}
 
 #define UNEXPECTED_SYSERROR(err, ...) \
@@ -340,7 +341,7 @@ mock_assert(const int result, const char *const expression,
 #else /* UNIT_TESTING */
 
 #define RUNTIME_CHECK(cond) \
-	((cond) ? (void)0 : isc_error_runtimecheck(__FILE__, __LINE__, #cond))
+	((cond) ? (void)0 : FATAL_ERROR("RUNTIME_CHECK(%s) failed", #cond))
 
 #endif /* UNIT_TESTING */
 
diff --git a/lib/isc/mem.c b/lib/isc/mem.c
index 9af25e600a..3ca55b6bb6 100644
--- a/lib/isc/mem.c
+++ b/lib/isc/mem.c
@@ -1236,9 +1236,7 @@ isc__mempool_destroy(isc_mempool_t **restrict mpctxp FLARG) {
 #endif
 
 	if (mpctx->allocated > 0) {
-		UNEXPECTED_ERROR(
-			"isc_mempool_destroy(): mempool %s leaked memory",
-			mpctx->name);
+		UNEXPECTED_ERROR("mempool %s leaked memory", mpctx->name);
 	}
 	REQUIRE(mpctx->allocated == 0);