diff --git a/CMakeLists.txt b/CMakeLists.txt
index 52e3f90059..91b660e52c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1105,7 +1105,7 @@ if(SDL_LIBC)
         #include <stddef.h>
         #include <iconv.h>
         int main(int argc, char **argv) {
-            return iconv_open(NULL,NULL);
+            return !iconv_open(NULL,NULL);
         }" ICONV_IN_LIBC)
 
       cmake_push_check_state()
@@ -1114,7 +1114,7 @@ if(SDL_LIBC)
         #include <stddef.h>
         #include <iconv.h>
         int main(int argc, char **argv) {
-            return iconv_open(NULL,NULL);
+            return !iconv_open(NULL,NULL);
         }" ICONV_IN_LIBICONV)
       cmake_pop_check_state()