Add restrictions about NULL passed to ck_assert_str_* macros

diff --git a/doc/check.texi b/doc/check.texi
index a948a2912ba7c7da90e3c27dd7a7e751b6283082..7391aa984a3109622b9fd17f14b33a9bae8e44ee 100644 (file)
--- a/doc/check.texi
+++ b/doc/check.texi
@@ -1198,10 +1198,11 @@ floating point value (@code{long double}) instead.
 
 Compares two null-terminated @code{char *} string values, using the
 @code{strcmp()} function internally, and displays predefined message
-with condition and input parameter values on failure.  The comparison
+with condition and input parameter values on failure. The comparison
 operator is again indicated by last two letters of the function name.
 @code{ck_assert_str_lt(a, b)} will pass if the unsigned numerical value
 of the character string @code{a} is less than that of @code{b}.
+If a NULL pointer would be passed to any comparison macro than check would fail.
 
 @item ck_assert_ptr_eq
 @itemx ck_assert_ptr_ne