adding RPATH to Sybase.so

jklowden has asked for the wisdom of the Perl Monks concerning the following question:

Building DBD::Sybase, I want to add /usr/local/dept/lib to the RPATH in the .so. Defining CCFLAGS or LDDLFLAGS on the Makefile.PL command line doesn't work. Mr. Peppler suggested I try here. I will forward any fix to him for future versions.

Is there another variable that works?
If not, how to modify Makefile.PL such that LDDLFLAGS works?

A normal invocation produces a link command like this:

gcc     -L/usr/local/dept/lib \
        -shared \
        -O2 \
        -g \
        -pipe \
        -Wall \
        -Wp,-D_FORTIFY_SOURCE=2 \
        -fexceptions \
        -fstack-protector \
        --param=ssp-buffer-size=4 \
        -m64 \
        -mtune=generic Sybase.o dbdimp.o \
        -o blib/arch/auto/DBD/Sybase/Sybase.so
[download]

I can add the RPATH manually by relinking thus:

$ sh -x relink && readelf -d blib/arch/auto/DBD/Sybase/Sybase.so | gre
+p -i rpath
+ gcc -L/usr/local/dept/lib -Wl,-R/usr/local/dept/lib -shared -O2 -g -
+pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --p
+aram=ssp-buffer-size=4 -m64 -mtune=generic Sybase.o dbdimp.o -o blib/
+arch/auto/DBD/Sybase/Sybase.so
 0x000000000000000f (RPATH)              Library rpath: [/usr/local/de
+pt/lib]
[download]

but using LDDLFLAGS damages the command line:

$ perl Makefile.PL PREFIX=$DEPT/perl LDDLFLAGS=-Wl,-R$DEPT/lib < answe
+rs && rm -f nohup.out && nohup make || grep ^gcc nohup.out | tail -1
Unknown Client Library version - assuming FreeTDS.
...
Writing Makefile for DBD::Sybase
nohup: appending output to `nohup.out'
gcc  -Wl,-R/usr/local/dept/lib Sybase.o dbdimp.o  -o blib/arch/auto/DB
+D/Sybase/Sybase.so
[download]

Many thanks. --jkl

Comment on adding RPATH to Sybase.so Select or Download Code

Replies are listed 'Best First'.
Re: adding RPATH to Sybase.so by almut (Canon) on Jan 12, 2010 at 20:14 UTC
I think you're out of luck with adding to `LDDLFLAGS`, but you could try setting `WriteMakefile( ... dynamic_lib => { OTHERLDFLAGS => '-Wl,-rpath,/usr/local/dept/lib' +}, ... );` [download] in `Makefile.PL` — which should achieve the same effect. `OTHERLDFLAGS` is being inserted a little later on the linker command line, i.e. `$(LD) $(LDDLFLAGS) $(LDFROM) $(OTHERLDFLAGS) -o $@ $(MYEXTLIB) ...`, but that's not a problem, as it doesn't matter at which position the rpath option occurs.	[reply] [d/l] [select]
Re^2: adding RPATH to Sybase.so by jklowden (Novice) on Jan 13, 2010 at 17:11 UTC
The story is there's no general answer. If LDDLFLAGS is overridden on the command line (LDDLFLAGS=-R/yada/yada) the value replaces what would ordinarily be there, because it overrides the value set by the hash passed to WriteMakefile in Makefile.PL. That is, WriteMakefile examines @ARGV for variable=value pairs and takes what it finds as overrides. (Observed behavior; I can't find the source code.) To extend LDDLFLAGS, one would have to know how Makefile.PL sets it. I don't know of any way to do that except by examining the sources. (Afaik there's no MakeMaker option to print variable values, although I suppose -qp could be passed to make(1) to do that instead.) Peeking inside Makefile.PL, one can easily see that LDDLFLAGS is set to the contanenation "-L$Sybase/lib" and $Config::Config{lddlflags}. So the hack would be something like: `perl Makefile.PL LDDLFLAGS=$(perl -e'use Config; print qq("-L$ENV{SYBASE}/lib $Config{lddlflags} -R/yada")')` which I guess is OK. Extending your suggestion, I added a new --other_dlflags option to Makefile.PL and sent a patch to Michael Peppler. Perhaps 1.10 will be a little easier to use. :-)	[reply] [d/l]