LD_LIBRARY_PATH setting

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

I need to modify the variable $LD_LIBRARY_PATH for some of my perl applications

Following some recommendations of the list, I tried in my perl application:

BEGIN {
 $ENV{LD_LIBRARY_PATH} = "/usr/local/gsl-1/lib" ;
# exec 'env', $^X, $0, @ARGV ;
 }
[download]

Actually, exec 'env', $^X, $0, @ARGV ; does not work

However, if I run

LD_LIBRARY_PATH=/usr/local/gsl-1/lib ./myperl.pl

It woks fine

How can I modify the LD_LIBRARY_PATH inside the perl file?

Patrick Dupre Universite du Littoral, FR Dunkirk

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Re: LD_LIBRARY_PATH setting by Corion (Patriarch) on Aug 05, 2016 at 18:31 UTC
On most operating systems, `$^X` contains the full path to the `perl` executable used to run your script, so you should not need to involve `env`. Your approach is the correct approach to restart your Perl script with added parameters, but you need to add one more parameter that indicates that your Perl script has restarted itself already: `BEGIN { if( ! $ENV{PDUPRE_RESTART}) { $ENV{LD_LIBRARY_PATH} = '...'; $ENV{PDUPRE_RESTART} = 1; exec $0, '--restarted', @ARGV }; }; ...` [download]	[reply] [d/l] [select]
Re^2: LD_LIBRARY_PATH setting by pdupre (Acolyte) on Aug 05, 2016 at 18:40 UTC
Thank But it still does not work! it just freezes and finally (after a timeout?) ignores what is in the enclosure Patrick Dupre Universite du Littoral, FR Dunkirk	[reply]
Re^3: LD_LIBRARY_PATH setting by Corion (Patriarch) on Aug 05, 2016 at 19:00 UTC
Maybe you can print some output so you see what is happening? Alternatively, trace your program with `truss` or `strace` to see what system calls it makes. Maybe you can post a short, self-contained example of the program you're actually running so we can reproduce your problem exactly?	[reply] [d/l] [select]
Re^4: LD_LIBRARY_PATH setting by pdupre (Acolyte) on Aug 05, 2016 at 19:08 UTC
Re^5: LD_LIBRARY_PATH setting by Corion (Patriarch) on Aug 05, 2016 at 19:14 UTC
Some notes below your chosen depth have not been shown here
Re: LD_LIBRARY_PATH setting by Anonymous Monk on Aug 05, 2016 at 19:15 UTC
LD_LIBRARY_PATH is for when you want to run a program and change which .so gets loaded, its like $PATH or %PATH%, Its not for compiling stuff like LIBS argument to Makefile.PL	[reply]
Re^2: LD_LIBRARY_PATH setting by Anonymous Monk on Aug 05, 2016 at 19:26 UTC
See also Devel::PL_origargv And maybe even :) Should I set LD_LIBRARY_PATH?, Why LD_LIBRARY_PATH is bad	[reply]
Re^2: LD_LIBRARY_PATH setting by Anonymous Monk on Aug 05, 2016 at 19:20 UTC
Oh, sorry , I got confused, I am wrong, you're trying the right direction	[reply]
Re: LD_LIBRARY_PATH setting by duyet (Friar) on Aug 06, 2016 at 12:11 UTC
When i need a path for my script i just included in the @INC, ie. `BEGIN { # ... unshift @INC, '/usr/local/gsl-1/lib'; # .. }` [download]	[reply] [d/l]
Re^2: LD_LIBRARY_PATH setting by Corion (Patriarch) on Aug 06, 2016 at 12:37 UTC
`$ENV{LD_LIBRARY_PATH}` is where unixish/linuxish systems go looking for system libraries. This comes into play when Perl libraries need to load system libraries. `@INC` is where Perl goes looking for Perl modules/Perl libraries.	[reply] [d/l] [select]
Re^3: LD_LIBRARY_PATH setting by Anonymous Monk on Aug 06, 2016 at 14:32 UTC
Worth adding that it should be possible to compile the related perl .so modules with a path to their dependencies, if necessary. The CC option `-Wl,--rpath=/path/to/libs` is passed to linker; resulting shared objects ought to load without custom `LD_LIBRARY_PATH`. So it's a matter of properly done module install.	[reply] [d/l] [select]