Re: [dev] ii: how to process out in a pipeline and still page with less

From: Hadrien Lacour <hadrien.lacour_AT_posteo.net>
Date: Sat, 28 May 2022 08:38:49 +0000

On Sat, May 28, 2022 at 03:33:16AM +0000, Rodrigo Martins wrote:
> Hello,
>
> The problem here is I/O buffering. I suspect it to happen in the C standard library, specifically on the printf function family. If I recall, the C standard says stdio is line-buffered when the file is an interactive device and let's it be fully buffered otherwise. This is likely why you see different behavior with and without less on the pipeline.
> I don't yet have a clear solution to this problem that doesn't involve modifying each program in the pipeline, but I've annexed a C source as an example that may be used in place of tr to replace single chars. This program is not supposed to buffer any I/O.
> I see tee "shall not buffer output". Another possibility is the setbuf function, but I'm not sure it can be used without editing each program. More investigation is needed.
>
> Rodrigo.

You can use stdbuf(1) to modify that aspect without touching the program source
itself.
Received on Sat May 28 2022 - 10:38:49 CEST