+@item
+When formatting an integer with grouping flag, this function inserts thousands
+separators even in the "C" locale on some platforms:
+NetBSD 5.1.
+@item
+Attempting to write to a read-only stream fails with @code{EOF} but
+does not set the error flag for @code{ferror} on some platforms:
+glibc 2.13, cygwin 1.7.9.