Subject: Re: [PATCH 2/4] kwset: allow building with GCC 8

From: SZEDER Gábor <[email-masked]>
Date: Fri, 14 Jun 2019 11:53:08 +0200

> Subject: Re: [PATCH 2/4] kwset: allow building with GCC 8

The subject could benefit from a "on Windows" at the end; 'kwset' and
compat/obstack can be build with GCC 8 and 9 just fine on some other
platforms.

On Thu, Jun 13, 2019 at 04:49:45AM -0700, Johannes Schindelin via GitGitGadget wrote:
> From: Johannes Schindelin <[email-masked]>
> 
> The kwset functionality makes use of the obstack code, which expects to
> be handed a function that can allocate large chunks of data. It expects
> that function to accept a `size` parameter of type `long`.
> 
> This upsets GCC 8 on Windows, because `long` does not have the same
> bit size as `size_t` there.
> 
> Now, the proper thing to do would be to switch to `size_t`. But this
> would make us deviate from the "upstream" code even further,

This is not entirely true: upstream already uses 'size_t', so the
switch would actually bring our copy closer to upstream.

But look out for the patches that I'll send out in a minute...

> making it
> hard to synchronize with newer versions, and also it would be quite
> involved because that `long` type is so invasive in that code.
> 
> Let's punt, and instead provide a super small wrapper around
> `xmalloc()`.
> 
> Signed-off-by: Johannes Schindelin <[email-masked]>
> ---
>  kwset.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/kwset.c b/kwset.c
> index 4fb6455aca..efc2ff41bc 100644
> --- a/kwset.c
> +++ b/kwset.c
> @@ -38,7 +38,13 @@
>  #include "compat/obstack.h"
>  
>  #define NCHAR (UCHAR_MAX + 1)
> -#define obstack_chunk_alloc xmalloc
> +/* adapter for `xmalloc()`, which takes `size_t`, not `long` */
> +static void *obstack_chunk_alloc(long size)
> +{
> +	if (size < 0)
> +		BUG("Cannot allocate a negative amount: %ld", size);
> +	return xmalloc(size);
> +}
>  #define obstack_chunk_free free
>  
>  #define U(c) ((unsigned char) (c))
> -- 
> gitgitgadget
>