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Re: environment variables in ld scripts

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We decided to build a bash script that generates the ld script with a multi-line echo.  Environment variables are part of the script, and are written to the temporary ld file as full path names.  The bash script them does a "chmod +x" on the ld file, and executes it.  The ld file can then be deleted because the bash script has the permanent contents.

Thanks very much,
Jay

On Tuesday, April 23, 2013 8:34:29 AM UTC-7, John Reiser wrote:
> > I have inherited an application that makes extensive use of ld scripts. ...
> 
> 
> 
> > -L $APP_LIBS -( -lnwiss -lr -)
> 
> The shell expands environment variable APP_LIBS here as part of a ld (or gcc) command line.
> 
> 
> 
> > @$APP_LIBS lib.ld
> 
> Inside a linker script, then ld does not expand shell environment variables.
> 
> 
> 
> > Is there a special notation for employing environment variables in ld scripts?
> 
> No; instead you must perform the expansion before invoking ld.
> 
> One way to do this is with a shell "Here Document" which is invoked by the syntax "<<".
> 
> See the documentation for any shell, such as "man bash" or "info bash".
> 
> Example:
> 
> 
> 
>    cat - > my_linker_script.txt  < 
>    @$APP_LIBS lib.ld
> 
>    EOF
> 
> 
> 
> The shell will expand "$APP_LIBS" as it reads the lines until EOF.
> 
> The utility program 'cat' then writes those lines to its stdout,
> 
> which in this case is re-directed to file "my_linker_script.txt".
> 
> 
> 
>    ld ... -T my_linker_script.txt ...
> 
> 
> 
> Use the file my_linker_script.txt with the already-expanded environment variables.
> 
> 
> 
> --

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environment variables in ld scripts Jay Braun <lyngwyst@gmail.com> - 2013-04-22 17:31 -0700
  Re: environment variables in ld scripts Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2013-04-23 14:50 +0300
  Re: environment variables in ld scripts John Reiser <jreiserfl@comcast.net> - 2013-04-23 08:34 -0700
    Re: environment variables in ld scripts Jay Braun <lyngwyst@gmail.com> - 2013-04-23 12:56 -0700
  Re: environment variables in ld scripts Jay Braun <lyngwyst@gmail.com> - 2013-04-23 12:56 -0700

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