Re: write past end of buffer in vasnprintf() implementation of %f

[Bruno Haible]

> +  for (size = 0; size <= 8; size++)
> +    {
> +      size_t length;
> +      char *result;
> +
> +      memcpy (buf, "DEADBEEF", 8);
> +      length = size;
> +      result = my_asnprintf (buf, &length, "%2.0f", 1.6314159265358979e+125);
> +      ASSERT (result != NULL);
> +      ASSERT (strcmp (result, 
> "163141592653589790215729350939528493057529598899734151772468186268423257777068536614838678161083520756952076273094236944990208")
>  == 0);

This new test case is a little bit too strict: it fails on Cygwin. This
patch fixes it.


2018-10-02  Bruno Haible  <br...@clisp.org>

        vasnprintf tests: Avoid test failure on Cygwin.
        * tests/test-vasnprintf.c (test_function): Change the test added on
        2018-09-23 to check only the 42 most significant digits.

diff --git a/tests/test-vasnprintf.c b/tests/test-vasnprintf.c
index 93d81d7..0cd17f9 100644
--- a/tests/test-vasnprintf.c
+++ b/tests/test-vasnprintf.c
@@ -70,7 +70,13 @@ test_function (char * (*my_asnprintf) (char *, size_t *, 
const char *, ...))
       length = size;
       result = my_asnprintf (buf, &length, "%2.0f", 1.6314159265358979e+125);
       ASSERT (result != NULL);
-      ASSERT (strcmp (result, 
"163141592653589790215729350939528493057529598899734151772468186268423257777068536614838678161083520756952076273094236944990208")
 == 0);
+      /* The exact result and the result on glibc systems is
+         
163141592653589790215729350939528493057529598899734151772468186268423257777068536614838678161083520756952076273094236944990208
+         On Cygwin, the result is
+         
163141592653589790215729350939528493057529600000000000000000000000000000000000000000000000000000000000000000000000000000000000
+       */
+      ASSERT (strlen (result) == 126);
+      ASSERT (memcmp (result, "163141592653589790215729350939528493057529", 
42) == 0);
       ASSERT (length == 126);
       if (size < 126 + 1)
         ASSERT (result != buf);