[U-Boot] [PATCH 2/2] RFC: Let linker create phy array

Mike Frysinger vapier at gentoo.org
Fri Feb 10 21:32:56 CET 2012


On Friday 10 February 2012 14:39:12 Albert ARIBAUD wrote:
> Le 07/02/2012 16:20, Mike Frysinger a écrit :
> > On Monday 06 February 2012 16:01:56 Albert ARIBAUD wrote:
> >> Le 06/02/2012 21:57, Mike Frysinger a écrit :
> >>>> Is there a keep attribute like the linker has for sections?
> >>> 
> >>> yes, __attribute__((used))
> >> 
> >> What is the point in adding a 'static' qualifier and a ((used))
> >> attribute, when not adding them in the first place gives the same
> >> result?
> > 
> > to control the visibility
> 
> I don't understand what you mean with this. Can you please elaborate?

no static means it has global elf visibility (other .c files can "extern" it, 
and you have to worry about symbol clashes):
$ gcc -x c -c - -o test.o <<<'int foo;' && readelf -s test.o | grep foo
     7: 0000000000000004     4 OBJECT  GLOBAL DEFAULT  COM foo

static means it has local elf visibility (other files don't get access, and you 
don't have to worry about symbol clashes):
$ gcc -x c -c - -o test.o <<<'static int foo;' && readelf -s test.o | grep foo
     5: 0000000000000000     4 OBJECT  LOCAL  DEFAULT    3 foo

imo, anything that should not be externally accessed should have "static".  
this is just good programming practice.
-mike
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