Re: Fun trick

On 1/7/2025 8:58 PM, Arne Vajhøj wrote:

During some troubleshooting over at VSI forum hb told me that
running a shareable image will execute LIB$INITIALIZE
functions.
 That made me write this:
 $ type lib.pas
[inherit('sys$library:pascal$lib_routines', 'sys$library:starlet')]
module lib(input, output);
 [global]
procedure check;
 var
    imgnam : varying [1024] of char;
 begin
    lib$getjpi(item_code := jpi$_imagname, resultant_string := imgnam.body, resultant_length := imgnam.length);
    if index(imgnam, ']libshr.EXE') > 0 then begin
       writeln('This is a shareable image to link against not run');
       $exit(ss$_normal);
    end;
end;
 [global]
procedure say;
 begin
    writeln('Hi');
end;
 end.
$ type prg.pas
program prg(input,output);
 [external]
procedure say; external;
 begin
    say;
end.
$ type trick.mar
         .title  trick
         .extrn  lib$initialize
         .psect  lib$initialize long,nopic,con,gbl,noshr,noexe,nowrt
         .address check
         .end
$ macro trick
$ pas lib
$ link/share=libshr lib + trick + sys$input/opt
SYMBOL_VECTOR=(say=PROCEDURE)
$
$ define/nolog libshr sys$disk:[]libshr
$ pas prg
$ link prg + sys$input/opt
libshr/share
$
$ run prg
Hi
$ run libshr
This is a shareable image to link against not run
 :-)
 Arne
 

Pascal has an [INITIALIZE] attribute that you can put on the PROCEDURE CHECK and the compiler should do the contribution to the LIB$INITIALIZE PSECT.
And you should include LIB$INITIALIZE (the code module, not the data PSECT) from STARLET when linking.  The x86 linker will do that for you, but the Alpha and Itanium linkers do not.