Re: [PATCH v3 1/2] pkt-line: add stdio packet write functions

[Jeff King <peff@peff.net>]

On Tue, Aug 31, 2021 at 11:34:43AM +0200, Jacob Vosmaer wrote:

> +void fwrite_or_die(FILE *f, const void *buf, size_t count)
> +{
> +	if (fwrite(buf, count, 1, f) != 1)
> +		die_errno("fwrite error");
> +}

One small oddity I noticed. The definition of fwrite is
fwrite(ptr, size, nmemb, strea), where we write "nmemb" items of "size"
bytes each. I'd argue we're writing "count" single bytes, so it should
be:

  if (fwrite(buf, 1, count, f) != count)

This matters a lot for fread(), where any read shorter than "count"
(e.g., due to EOF) would return "0" rather than a partial result. But I
have a hard time imagining an implementation of fwrite() where the
distinction would matter. And grepping around, we seem to have both
forms in our code base already. So it's probably fine.

-Peff