Attached is an updated patch that fixes the substr_6.f90
test that also prints a nul character to stdout. I don't
think there are any others.

Besides interfering with the debugging of the log corruption
I mentioned, printing nuls or control characters in tests is
also problematic for tools designed to post-process log files
(e.g., grep) that are intended to work with text files (i.e.,
files not containing nuls). Control characters can cause the
tools to fail in non-C locales (such as UTF-8).

On 04/09/2015 12:54 PM, Martin Sebor wrote:
> We've been debugging a problem where nul (and other control)
> characters have been randomly appearing in powerpc parallel
> build logs. In the process, I noticed that some of the nuls
> are readily reproducible. One such case is due to
> the pr32627.f03 test which verifies that Fortran programs
> can initialize character arrays from C strings. The test
> declares an array as big as the C string (including the
> terminating nul) and prints its value to stdout. This then
> causes the nul to appear in the log files.
>
> The attached patch changes the declaration of the Fortran
> array to match the number of non-nul characters. Tested on
> powerpc64.
>
> Martin