[FFmpeg-devel] [PATCH] configure: Make MSVC version grabbing more robust

[Martin Storsjö]

On Fri, 13 Jun 2025, Martin Storsjö wrote:

> When running plain "cl", to get the MSVC version, it prints the
> version header on stderr, while the usage instructions are printed
> on stdout. Usually, the version on stderr gets flushed first,
> so "head -n1" gets the line it expects, but some times (in particular
> when running MSVC wrapped in wine), it can get the usage line
> first.
>
> Redirect stdout to /dev/null, so we only grab the version among
> the lines printed to stderr. This should make the version number
> grabbing more robust.
>
> At least all relevant versions of MSVC seem to print this specifically
> to stderr, not stdout (so we don't risk to miss it); checked down
> to MSVC 2010.
> ---
> This should avoid the occasionally misdetected version number lines
> as seen at https://fate.ffmpeg.org/history.cgi?slot=x86_64-msvc2022-wine.
> ---
> configure | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)

Will push.

// Martin