Warn about non-standard format strings (pr12017)

This adds the -Wformat-non-standard flag (off by default,
enabled by -pedantic), which warns about non-standard
things in format strings (such as the 'q' length modifier,
the 'S' conversion specifier, etc.)

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@151154 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 1 insertions, 2 deletions

diff --git a/test/SemaCXX/format-strings.cpp b/test/SemaCXX/format-strings.cpp
index 74fc7a7810..314617d491 100644
--- a/test/SemaCXX/format-strings.cpp
+++ b/test/SemaCXX/format-strings.cpp
@@ -9,8 +9,7 @@ extern int vprintf(const char *restrict, va_list);
 }
 
 void f(char **sp, float *fp) {
-  // TODO: Warn that the 'a' length modifier is an extension.
-  scanf("%as", sp);
+  scanf("%as", sp); // expected-warning{{'a' is a non-standard length modifier}}
 
   // TODO: Warn that the 'a' conversion specifier is a C++11 feature.
   printf("%a", 1.0);