perl6 NativeCall doesn't find library on Darwin - shared-libraries

Question

I'm playing a bit with NativeCall to get familiar with that side of Perl6. Of course, I'm trying to load libstatgrab first (what else?).
So I start with easiest part - the host information. Since no cluster support yet, it's just one result - no worries for complication.
The code:
#!/usr/bin/env perl6
use v6;
use NativeCall;
enum sg_error (
SG_ERROR_NONE => 0,
SG_ERROR_INVALID_ARGUMENT => 1,
...
);
class sg_error_details is repr('CStruct') {
has int32 $.error;
has int32 $.errno_value;
has Str $.error_arg;
};
sub sg_init(int32 $ignore_errors) returns int32 is native('statgrab') { * };
enum sg_host_state (
sg_unknown_configuration => 0,
sg_physical_host => 1,
sg_virtual_machine => 2,
sg_paravirtual_machine => 3,
sg_hardware_virtualized => 4
);
class sg_host_info is repr('CStruct') {
has Str $.os_name;
has Str $.os_release;
has Str $.os_version;
has Str $.platform;
has Str $.hostname;
has uint32 $.bitwidth;
has int32 $.host_state;
has uint32 $.ncpus;
has uint32 $.maxcpus;
has uint64 $.uptime;
has uint64 $.systime;
};
sub sg_get_host_info(size_t is rw) returns Pointer is native('statgrab') is symbol('sg_get_host_info_r') { * };
sub sg_free_host_info(Pointer) is native('statgrab') is symbol('sg_free_stats_buf') { * };
sub MAIN() {
my int32 $ignore_errors = 0;
my $error = sg_init($ignore_errors);
if $error != SG_ERROR_NONE {
say "Maeh: $error";
exit 1;
}
my size_t $num_host_infos = 0;
my $res = sg_get_host_info($num_host_infos);
if $num_host_infos > 0 {
my $host_info = nativecast(sg_host_info, $res);
with $host_info {
say "You're using ", $_.os_name, " on ", $_.hostname;
}
}
sg_free_host_info($res);
}
Starting it (dumb) results in loading library error:
$ perl6 statgrab.p6
Cannot locate native library 'libstatgrab.dylib': dlopen(libstatgrab.dylib, 1): image not found
in method setup at /Users/sno/rakudo/share/perl6/sources/24DD121B5B4774C04A7084827BFAD92199756E03 (NativeCall) line 283
in method CALL-ME at /Users/sno/rakudo/share/perl6/sources/24DD121B5B4774C04A7084827BFAD92199756E03 (NativeCall) line 570
in sub MAIN at statgrab.p6 line 95
in block <unit> at statgrab.p6 line 93
Okay - giving it some search path:
$ LD_LIBRARY_PATH=/opt/pkg/lib:$LD_LIBRARY_PATH perl6 statgrab.p6
Cannot locate native library 'libstatgrab.dylib': dlopen(libstatgrab.dylib, 1): image not found
Same picture when using DYLD_LIBRARY_PATH - which is supported by dlopen(3) on Darwin, too.
But changing in the directory works:
$ (cd /opt/pkg/lib && perl6 /data/Projects/OSS/p6-Unix-Statgrab/statgrab.p6 )
You're using Darwin on ernie.[...]
Is there a lack of search path passthrough in the way how moarvm is called?

Answer 1

doug$ perl6 -v
This is Rakudo Star version 2018.10 built on MoarVM version 2018.10
implementing Perl 6.c.
On a fairly recent Rakudo Star on MacOS High Sierra, the script worked "out of the box" for me:
edited script to remove '...'.
Script failed to load the library (really missing!)
brew install libstatgrab
Script ran successfully:
vader:learning doug$ perl6 nativecall_mac_Sno.pl6
You're using Darwin on Vader.local
Homebrew installed the library as follows:
$ v /usr/local/lib
total 11904
-rw-r--r-- 1 doug admin 6080828 Sep 23 12:40 libmoar.dylib
lrwxr-xr-x 1 doug admin 51 Mar 23 11:02 libstatgrab.10.dylib# -> ../Cellar/libstatgrab/0.91/lib/libstatgrab.10.dylib
lrwxr-xr-x 1 doug admin 44 Mar 23 11:02 libstatgrab.a# -> ../Cellar/libstatgrab/0.91/lib/libstatgrab.a
lrwxr-xr-x 1 doug admin 48 Mar 23 11:02 libstatgrab.dylib# -> ../Cellar/libstatgrab/0.91/lib/libstatgrab.dylib
drwxr-xr-x 3 doug admin 102 Mar 23 11:02 pkgconfig/
For me, the perl6 executable is indeed a shell script, but it worked (there was no need to pass any extra LD_LIBRARY_PATH=...).
doug$ file `which perl6`
/Applications/Rakudo/bin/perl6: POSIX shell script text executable, ASCII text, with very long lines
doug$ set | grep LIBRARY
doug$
I have also had issues with my nativecall scripts finding the library, but have always solved them by fixing the library install and/or supplying 'LD_LIBRARY_PATH'.
Sorry this experience was Less Than Awesome for you