Re: new module lib-ignore; new section build_lib in MODULES.html

[Ralf Wildenhues]

Hi Bruno,

* Bruno Haible wrote on Wed, Jan 18, 2006 at 01:36:35PM CET:
> 
> One more question about this macro: What is the difference between
> -Xlinker and -Wl (apart from the slightly different syntax)? libtool and
> config.rpath sometimes use -Wl to pass an option to the linker and never
> -Xlinker,

This is true for config.rpath, but not for libtool, on both the
receiving (input to libtool) and the output side (the command line
libtool generates).

> whereas your macro uses sometimes -Xlinker and never -Wl.
> It appears that -Xlinker is supported only by gcc, and -Wl by other
> compilers too?

Both are supported by a number of compilers.  Neither are supported by
all compilers.  Likely, for some useful measures, -Wl, is supported by
more compilers.

> > I looked into doing this, and ran into some problems.
> > LDDPOSTPROC is set in such a way that configure needs to employ 'eval'
> > to use it, and then I ran into porting problems when using things like
> > 'eval "$LDDPROG ... $LDDPOSTPROC"' since LDDPROG began "LC_ALL=C ..."
> 
> The variables were not meant to be used with eval, just to be used
> without quotes, like this:
>      $LDDPROG program $LDDPOSTPROC

I tried to explain this before: the shell does the splitting into
commands before it does variable expansion.  Thus, a `|' (pipe) symbol
in a variable won't do what you intend, namely create a process pipe,
unless you use `eval'.  And if you use eval with the current ldd
module, information from $LDDPOSTPROC will be lost due to missing or
plainly wrong-for-eval quotation (e.g., white space information).

Cheers,
Ralf