diff --git a/package/rwmem/Config.in b/package/rwmem/Config.in
index 0fd9142e92..cd9a7f78f1 100644
--- a/package/rwmem/Config.in
+++ b/package/rwmem/Config.in
@@ -2,9 +2,14 @@ config BR2_PACKAGE_RWMEM
 	bool "rwmem"
 	depends on BR2_TOOLCHAIN_GCC_AT_LEAST_5
 	depends on BR2_INSTALL_LIBSTDCPP
+	depends on BR2_USE_WCHAR # fmt
 	select BR2_PACKAGE_FMT
 	select BR2_PACKAGE_INIH
 	help
 	  Simple program to read/write from/to any location in memory.
 
 	  https://github.com/tomba/rwmem
+
+comment "rwmem needs a toolchain w/ C++, wchar, gcc >= 5"
+	depends on !BR2_INSTALL_LIBSTDCPP || !BR2_USE_WCHAR || \
+		!BR2_TOOLCHAIN_GCC_AT_LEAST_5