diff --git a/test/input.output/file.streams/c.files/cstdio.pass.cpp b/test/input.output/file.streams/c.files/cstdio.pass.cpp
index 5c387cdc9..9b8212150 100644
--- a/test/input.output/file.streams/c.files/cstdio.pass.cpp
+++ b/test/input.output/file.streams/c.files/cstdio.pass.cpp
@@ -95,19 +95,19 @@ int main()
     static_assert((std::is_same<decltype(std::freopen("", "", fp)), std::FILE*>::value), "");
     static_assert((std::is_same<decltype(std::setbuf(fp,cp)), void>::value), "");
     static_assert((std::is_same<decltype(std::vfprintf(fp,"",va)), int>::value), "");
-    static_assert((std::is_same<decltype(std::fprintf(fp,"")), int>::value), "");
+    static_assert((std::is_same<decltype(std::fprintf(fp," ")), int>::value), "");
     static_assert((std::is_same<decltype(std::fscanf(fp,"")), int>::value), "");
-    static_assert((std::is_same<decltype(std::printf("")), int>::value), "");
-    static_assert((std::is_same<decltype(std::scanf("")), int>::value), "");
-    static_assert((std::is_same<decltype(std::snprintf(cp,0,"")), int>::value), "");
-    static_assert((std::is_same<decltype(std::sprintf(cp,"")), int>::value), "");
+    static_assert((std::is_same<decltype(std::printf(" ")), int>::value), "");
+    static_assert((std::is_same<decltype(std::scanf(" ")), int>::value), "");
+    static_assert((std::is_same<decltype(std::snprintf(cp,0," ")), int>::value), "");
+    static_assert((std::is_same<decltype(std::sprintf(cp," ")), int>::value), "");
     static_assert((std::is_same<decltype(std::sscanf("","")), int>::value), "");
     static_assert((std::is_same<decltype(std::vfprintf(fp,"",va)), int>::value), "");
     static_assert((std::is_same<decltype(std::vfscanf(fp,"",va)), int>::value), "");
-    static_assert((std::is_same<decltype(std::vprintf("",va)), int>::value), "");
+    static_assert((std::is_same<decltype(std::vprintf(" ",va)), int>::value), "");
     static_assert((std::is_same<decltype(std::vscanf("",va)), int>::value), "");
-    static_assert((std::is_same<decltype(std::vsnprintf(cp,0,"",va)), int>::value), "");
-    static_assert((std::is_same<decltype(std::vsprintf(cp,"",va)), int>::value), "");
+    static_assert((std::is_same<decltype(std::vsnprintf(cp,0," ",va)), int>::value), "");
+    static_assert((std::is_same<decltype(std::vsprintf(cp," ",va)), int>::value), "");
     static_assert((std::is_same<decltype(std::vsscanf("","",va)), int>::value), "");
     static_assert((std::is_same<decltype(std::fgetc(fp)), int>::value), "");
     static_assert((std::is_same<decltype(std::fgets(cp,0,fp)), char*>::value), "");