Calling Go Function from java using JNI: Library Not loaded [duplicate] - scala

Question

I want to set under Mac OSX the runtime path of an executable (for the linker) at compile time, such that shared libraries at non-standard locations are found by the dynamic linker at program start.
Under Linux this is possible with -Xlinker -rpath -Xlinker /path/to (or using -Wl,-rpath,/path/to) and under Solaris you can add -R/path/to to the compiler command line.
I found some information that Mac OS X gcc has -rpath support since 10.5, i.e. since ~ 2008.
I tried to get it working with a minimal example - without success:
$ cat blah.c
int blah(int b)
{
return b+1;
}
And:
$ cat main.c
#include <stdio.h>
int blah(int);
int main ()
{
printf("%d\n", blah(22));
return 0;
}
Compiled it like this:
$ gcc -c blah.c
$ gcc -dynamiclib blah.o -o libblah.dylib
$ gcc main.c -lblah -L`pwd` -Xlinker -rpath -Xlinker `pwd`/t
Now the test:
$ mkdir t
$ mv libblah.dylib t
$ ./a.out
dyld: Library not loaded: libblah.dylib
Referenced from: /Users/max/test/./a.out
Reason: image not found
Trace/BPT trap
Thus the question: How to I set the runtime path for the linker under Mac OSX?
Btw, setting DYLD_LIBRARY_PATH works - but I don't want to use this hack.
Edit: Regarding otool -L:
$ otool -L a.out
a.out:
libblah.dylib (compatibility version 0.0.0, current version 0.0.0)
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.2.1)
It seems that otool -L only prints the library names (and probable the locations at link time) the executable was linked against and no runtime path information.

Answer 1

Found by experimentation, and inspecting the command lines generated by Xcode for a reference rpath demo project by Dave Driblin:
otool -L shows you the install name of the linked libraries. To get #rpath to work, you need to change the install name of the library:
$ gcc -dynamiclib blah.o -install_name #rpath/t/libblah.dylib -o libblah.dylib
$ mkdir t ; mv libblah.dylib t/
$ gcc main.c -lblah -L`pwd`/t -Xlinker -rpath -Xlinker `pwd`