From: Junio C Hamano <gitster@pobox•com>
To: Elia Pinto <gitter.spiros@gmail•com>
Cc: git@vger•kernel.org, peff@peff•net
Subject: Re: [PATCH v3] git-compat-util.h: implement a different ARRAY_SIZE macro for for safely deriving the size of array
Date: Thu, 30 Apr 2015 10:41:30 -0700 [thread overview]
Message-ID: <xmqqd22l1pkl.fsf@gitster.dls.corp.google.com> (raw)
In-Reply-To: <1430397854-28908-1-git-send-email-gitter.spiros@gmail.com> (Elia Pinto's message of "Thu, 30 Apr 2015 14:44:14 +0200")
Elia Pinto <gitter.spiros@gmail•com> writes:
> +#if defined(__GNUC__) && (__GNUC__ >= 3)
> +# if GIT_GNUC_PREREQ(3, 1)
> + /* &arr[0] degrades to a pointer: a different type from an array */
> +# define BARF_IF_IS_NOT_AN_ARRAY(arr) \
> + BUILD_ASSERT_OR_ZERO(!__builtin_types_compatible_p(typeof(arr), \
> + typeof(&(arr)[0])))
> +# else
> +# define BARF_IF_IS_NOT_AN_ARRAY(arr) 0
> +# endif
> +#endif
> +/*
> + * ARRAY_SIZE - get the number of elements in a visible array
> + * <at> x: the array whose size you want.
> + *
> + * This does not work on pointers, or arrays declared as [], or
> + * function parameters. With correct compiler support, such usage
> + * will cause a build error (see the build_assert_or_zero macro).
> + */
> +#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]) + BARF_IF_IS_NOT_AN_ARRAY(x))
> +
> #define bitsizeof(x) (CHAR_BIT * sizeof(x))
>
> #define maximum_signed_value_of_type(a) \
Hmmmmmmmm.
CC ws.o
ws.c: In function 'parse_whitespace_rule':
ws.c:46:3: error: unknown type name 'typeof'
for (i = 0; i < ARRAY_SIZE(whitespace_rule_names); i++) {
^
$ gcc --version
gcc (Ubuntu 4.8.2-19ubuntu1) 4.8.2
Copyright (C) 2013 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There
is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.
next prev parent reply other threads:[~2015-04-30 17:41 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-30 12:44 [PATCH v3] git-compat-util.h: implement a different ARRAY_SIZE macro for for safely deriving the size of array Elia Pinto
2015-04-30 17:20 ` Junio C Hamano
2015-04-30 17:41 ` Junio C Hamano [this message]
2015-04-30 17:44 ` Jeff King
2015-04-30 17:54 ` Junio C Hamano
2015-04-30 17:59 ` Junio C Hamano
2015-04-30 18:19 ` Jeff King
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