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From: Slava Ovsiienko <viacheslavo@mellanox.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: "dev@dpdk.org" <dev@dpdk.org>, Matan Azrad <matan@mellanox.com>,
	Raslan Darawsheh <rasland@mellanox.com>,
	"ferruh.yigit@intel.com" <ferruh.yigit@intel.com>
Subject: Re: [dpdk-dev] [PATCH] net/mlx5: fix compilation issue with gcc pragma
Date: Tue, 1 Oct 2019 17:15:46 +0000	[thread overview]
Message-ID: <AM4PR05MB3265FE85DC52039D469F3EB6D29D0@AM4PR05MB3265.eurprd05.prod.outlook.com> (raw)
In-Reply-To: <20191001075429.70a08442@hermes.lan>

> -----Original Message-----
> From: Stephen Hemminger <stephen@networkplumber.org>
> Sent: Tuesday, October 1, 2019 17:54
> To: Slava Ovsiienko <viacheslavo@mellanox.com>
> Cc: dev@dpdk.org; Matan Azrad <matan@mellanox.com>; Raslan
> Darawsheh <rasland@mellanox.com>; ferruh.yigit@intel.com
> Subject: Re: [dpdk-dev] [PATCH] net/mlx5: fix compilation issue with gcc
> pragma
> 
> On Tue,  1 Oct 2019 11:10:23 +0000
> Viacheslav Ovsiienko <viacheslavo@mellanox.com> wrote:
> 
> > +#if defined(RTE_TOOLCHAIN_GCC) && (GCC_VERSION >= 40600)
> #pragma GCC
> > +diagnostic push
> >  #pragma GCC diagnostic ignored "-Wformat-nonliteral"
> > +#endif
> > +	/* Use safe format to check maximal buffer length. */
> >  	while (fscanf(file, format, ifname) == 1) { -#pragma GCC diagnostic
> > error "-Wformat-nonliteral"
> > +#if defined(RTE_TOOLCHAIN_GCC) && (GCC_VERSION >= 40600)
> #pragma GCC
> > +diagnostic pop #endif
> 
> This is messy, is there not a better way to do this?

At least I did not find one.

The GCC compile-time format checking feature is nice in general and it worth 
to be engaged. The legitimate fscanf() usage with variable format parameter
causes GCC to emit error/warning, so we should suppress these ones for this
single line. ICC does not emit warning and does not recognize GCC pragmas.
Clang just does not recognize fscanf().

Should we use "#ifndef __INTEL_COMPILER" (typical workaround for
GCC diagnostic pragma in DPDK)? I'm not sure, It is not completely correct.

The alternative I see is to implement dedicated routine to read words from the file,
but it means more code and more run-time resources. It seems not to be 
the right way to push compile-time issues resolving to the run-time.

Defining the macro is not relevant here because this is a single case.

WBR, Slava



  reply	other threads:[~2019-10-01 17:15 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-01 11:10 Viacheslav Ovsiienko
2019-10-01 14:54 ` Stephen Hemminger
2019-10-01 17:15   ` Slava Ovsiienko [this message]
2019-10-01 23:41     ` Stephen Hemminger
2019-10-02  6:15       ` Slava Ovsiienko
2019-10-02  6:55         ` Slava Ovsiienko
2019-10-02 11:54           ` Ferruh Yigit
2019-10-02 12:40             ` Slava Ovsiienko
2019-10-02  6:08 ` [dpdk-dev] [PATCH v2] " Viacheslav Ovsiienko
2019-10-02 12:36 ` [dpdk-dev] [PATCH v3] " Viacheslav Ovsiienko
2019-10-02 16:19   ` Ferruh Yigit

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