[Buildroot] [PATCH 1/2] pkgconf: pkg-config.in: double quote $@

Gaël PORTAY gael.portay at savoirfairelinux.com
Wed Feb 21 23:48:54 UTC 2018


Thomas,

On Wed, Feb 21, 2018 at 10:13:16PM +0100, Thomas Petazzoni wrote:
> Hello,
> 
> On Wed, 21 Feb 2018 15:55:54 -0500, Gaël PORTAY wrote:
> > Double quote $@ to prevent from splitting elements.
> > 
> > Signed-off-by: Gaël PORTAY <gael.portay at savoirfairelinux.com>
> 
> Could you give more details about what this is fixing, i.e a specific
> scenario that is fixed by this patch ?

In the case pkgconf, I can not see a real situation where this patch
fixes an issue.

There is an important difference between $@ and "$@". The shell expands
"$@" as "$1" "$2" "$3"... while it expands $@ as $1 $2 $3.

With the second form, we losts spaces in positional parameters.

As example, the following call

	pkg-config --cflags "one two" three

is wrapped as

	pkgconf --cflags one two three

while we are expecting

	pkgconf --cflags "one two" three

"$@" is really useful when writing wrappers. It passes the positional
arguments *as* they are given.

> 
> Thanks!
> 
> Thomas
> -- 
> Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
> Embedded Linux and Kernel engineering
> http://bootlin.com

Regards,
Gael


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