Specifying command line arguments in a file?

[Robert Schweikert <rjschwei at hks dot com>]

Hi,

I would like to specify command line options for gcc or ld in a file.
All I have found so far by looking at the documentation is that I can
write a linker script using the ld command language. However, this is
not working for me as described below.

Background:

I am trying to generate a shared library by linking an object file (.o)
an archive (.a) and some other shared library (.so) on a linux system.
When linking the object code (.o) file I want to force some symbols to
be undefined, such that they are linked from the archive, where they are

defined. If I use the -u option on the g++ command line this is working.

However, since I have a number of symbols and don't want to list them
all on the command line I want to use a text file to provide these
arguments. I have tried a linker script, specified with -Wl,scriptname
on the g++ command line, but is not working for me at all. The script
basically has a bunch of EXTERN definitions in it, and according to the
documentation this is the same as -u on the command line. Here is a
snippet.

EXTERN(ucorr_);
EXTERN(uel_);
EXTERN(uexpan_);
EXTERN(uexternaldb_);
EXTERN(ufield_);
EXTERN(ufluid_);

There are no complaints during linking, but when I try to load the
library created with this linker script I get the following error.

error while loading shared libraries: undefined symbol: uexternaldb_

Now if I use the same link command with the exception of replacing the
link script name with a -u uexternaldb_ everything works as expected.
What am I messing up here?

The info pages state the following:

`EXTERN(SYMBOL SYMBOL ...)'
     Force SYMBOL to be entered in the output file as an undefined
     symbol.  Doing this may, for example, trigger linking of additional

     modules from standard libraries.  You may list several SYMBOLs for
     each `EXTERN', and you may use `EXTERN' multiple times.  This
     command has the same effect as the `-u' command-line option.

Any help is much appreciated. This is on a SuSE 7.1 and RedHat 6.2
system.

SuSE:
ld -v
GNU ld version 2.10.91 (with BFD 2.10.0.33)

RedHat:
ld -v
GNU ld version 2.9.5 (with BFD 2.9.5.0.22)


Thanks,
Robert



--
Robert Schweikert                   MAY THE SOURCE BE WITH YOU
                                             LINUX