Re: export_dynamic_flag_spec

[Gary V. Vaughan]

Hi Sam,

On 10 Jun 2010, at 02:35, Sam Steingold wrote:
> On 6/9/10, Gary V. Vaughan <address@hidden> wrote:
>> On 10 Jun 2010, at 01:51, Sam Steingold wrote:
>>> EXPORT_DYNAMIC_FLAG_SPEC='@EXPORT_DYNAMIC_FLAG_SPEC@'
>>> 
>>> alas, instead of
>>> 
>>> EXPORT_DYNAMIC_FLAG_SPEC='-Wl,--export-dynamic'
>>> 
>>> foo.sh contains this:
>>> 
>>> EXPORT_DYNAMIC_FLAG_SPEC='${wl}--export-dynamic'
>>> 
>>> which is obviously wrong.
>> 
>> 
>> No, it's quite deliberate.
> 
> what I meant "wrong for my purposes".
> 
>>> So, how do I get the full correct value of export_dynamic_flag_spec?
>> 
>> Choose or extract an appropriate value for $wl from libtool, something along
>> the lines of:
>> 
>>  eval `libtool --tag=CC --config|grep '^wl='`
>> 
>> Generally when a libtool variable name ends with '_spec', that means it
>> relies on being evaluated with an appropriate environment before use.
> 
> It appears that this:
> 
> wl=$lt_prog_compiler_wl eval
> EXPORT_DYNAMIC_FLAG_SPEC=\"$export_dynamic_flag_spec\"
> AC_SUBST(EXPORT_DYNAMIC_FLAG_SPEC)dnl
> 
> does the trick for me at this time.
> is it OK to use? (as in "will not randomly break in the future")

$ grep lt_prog_compiler_wl ~/libtool--devo--0/doc/*.texi

Well, that's a private undocumented interface, so it might very well change.

$ grep -- '--config' ~/libtool--devo--0/doc/*.texi
.../doc/libtool.texi:@item --config
.../doc/libtool.texi:had to run the script with @option{--config} and grep 
through the
.../doc/libtool.texi:obviously it cannot be called for @option{--config} 
details anymore.  If
.../doc/libtool.texi:When people report bugs, ask them to use the 
@option{--config},

I'd recommend calling LT_OUTPUT to force the libtool script to be written,
and then calling it with --config as I showed above to fetch the value of $wl
with a documented interface.

Cheers,
-- 
Gary V. Vaughan (address@hidden)