[Piglit] [PATCH] util: fix Windows stdout/stderr buffering

[Jose Fonseca]

On 07/06/17 21:17, Brian Paul wrote:
> Windows doesn't immediately flush stdout/stderr after printf().
> Use setbuf() to disable buffering on Windows.

Hmm, I thought that Windows immediately flushed stderr/stdout when it is 
a TTY, just like Linux.

Most like stdout/stderr is not a TTY.  That is

   isatty(STDOUT_FILENO)
   isatty(STDERR_FILENO)

returns false.

Are you using a Cygwin shell/terminal? Perhaps that's the issue -- mayve 
it's redirecting stdout/stderr to a pipe behind your back.

At any rate, it doesn't hurt to disable buffering, to cover all cases, 
so this is

Reviewed-by: Jose Fonseca <jfonseca at vmware.com>

though it might be worth rephrasing the comment, as I don't think 
Windows differs from Linux in this regard.

Jose

> Refactor the init code a bit to avoid calling setbuf() from some
> arbitrary place otherwise.
> ---
>   tests/util/piglit-framework-gl.h |  2 +-
>   tests/util/piglit-util.c         | 24 +++++++++++++++++++++++-
>   tests/util/piglit-util.h         |  2 +-
>   3 files changed, 25 insertions(+), 3 deletions(-)
> 
> diff --git a/tests/util/piglit-framework-gl.h b/tests/util/piglit-framework-gl.h
> index 992f28a..970fd55 100644
> --- a/tests/util/piglit-framework-gl.h
> +++ b/tests/util/piglit-framework-gl.h
> @@ -271,7 +271,7 @@ piglit_gl_test_run(int argc, char *argv[],
>           {                                                                    \
>                   struct piglit_gl_test_config config;                         \
>                                                                                \
> -                piglit_disable_error_message_boxes();                        \
> +                piglit_general_init();                                       \
>                                                                                \
>                   piglit_gl_test_config_init(&config);                         \
>                                                                                \
> diff --git a/tests/util/piglit-util.c b/tests/util/piglit-util.c
> index 6b34c46..15a178b 100644
> --- a/tests/util/piglit-util.c
> +++ b/tests/util/piglit-util.c
> @@ -317,7 +317,7 @@ piglit_report_subtest_result(enum piglit_result result, const char *format, ...)
>   }
>   
>   
> -void
> +static void
>   piglit_disable_error_message_boxes(void)
>   {
>   	/* When Windows' error message boxes are disabled for this process (as
> @@ -354,6 +354,28 @@ piglit_disable_error_message_boxes(void)
>   }
>   
>   
> +static void
> +piglit_set_line_buffering(void)
> +{
> +	/* Windows doesn't immediately flush stdout/stderr after printf
> +	 * calls as we see on Linux.  To get immediate flushing, we disable
> +	 * buffering here.
> +	 */
> +#ifdef _WIN32
> +	setbuf(stdout, NULL);
> +	setbuf(stderr, NULL);
> +#endif
> +}
> +
> +
> +void
> +piglit_general_init(void)
> +{
> +	piglit_disable_error_message_boxes();
> +	piglit_set_line_buffering();
> +}
> +
> +
>   void
>   piglit_set_rlimit(unsigned long lim)
>   {
> diff --git a/tests/util/piglit-util.h b/tests/util/piglit-util.h
> index b30ae07..ad00817 100644
> --- a/tests/util/piglit-util.h
> +++ b/tests/util/piglit-util.h
> @@ -414,7 +414,7 @@ void piglit_set_timeout(double seconds, enum piglit_result timeout_result);
>   void piglit_report_subtest_result(enum piglit_result result,
>   				  const char *format, ...) PRINTFLIKE(2, 3);
>   
> -void piglit_disable_error_message_boxes(void);
> +void piglit_general_init(void);
>   
>   extern void piglit_set_rlimit(unsigned long lim);
>   
>