Re: [PATCH 1/6] Add memory pool library

From: Jonathan Nieder <jrnieder@gmail.com>
To: Ramkumar Ramachandra <artagnon@gmail.com>
Cc: Git Mailing List <git@vger.kernel.org>,
	David Michael Barr <david.barr@cordelta.com>,
	Sverre Rabbelier <srabbelier@gmail.com>,
	Michael J Gruber <git@drmicha.warpmail.net>,
	Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH 1/6] Add memory pool library
Date: Sat, 12 Jun 2010 01:42:51 -0500	[thread overview]
Message-ID: <20100612064250.GB2549@burratino> (raw)
In-Reply-To: <1276175389-6185-2-git-send-email-artagnon@gmail.com>

Ramkumar Ramachandra wrote:

> +#define obj_pool_gen(pre, obj_t, initial_capacity) \
> +static struct { \
> +	uint32_t committed; \
> +	uint32_t size; \
> +	uint32_t capacity; \
> +	obj_t *base; \
> +	FILE *file; \
> +} pre##_pool = { 0, 0, 0, NULL, NULL}; \
> +static void pre##_init(void) \
> +{ \
[...]

This defines a family of functions and not all pools use them all.
One workaround is to annotate them, like this:

 #ifdef __GNUC__
 #define MAYBE_UNUSED __attribute__((__unused__))
 #else
 #define MAYBE_UNUSED
 #endif

 #define obj_pool_gen(pre, obj_t, initial_capacity) \
 ... \
 static MAYBE_UNUSED void pre##_init(void) \
 { \
 ...

Could that work here?

The “unused” attribute was added in gcc 2.7.

Jonathan