(dynamic-link "libm") fails [was Re: Integrate Guile with GNU Scientific Library]

[Matt Wette]

  scheme@(guile-user)> (dynamic-link "libffi")
  $1 = #<dynamic-object "libffi">

  scheme@(guile-user)> (dynamic-link "libm")
  ERROR: In procedure dynamic-link:
  In procedure dynamic-link: file: "libm", message: "file not found"

Both libraries are linked into guile, so being already linked is not an 
issue.

However:

  mwette$ file /usr/lib/x86_64-linux-gnu/libm.so
/usr/lib/x86_64-linux-gnu/libm.so: ASCII text

mwette$ cat /usr/lib/x86_64-linux-gnu/libm.so
/* GNU ld script
*/
OUTPUT_FORMAT(elf64-x86-64)
GROUP ( /lib/x86_64-linux-gnu/libm.so.6  AS_NEEDED ( 
/usr/lib/x86_64-linux-gnu/libmvec_nonshared.a 
/lib/x86_64-linux-gnu/libmvec.so.1 ) )

This is an apparent redirection.   I think this is a bug (or feature) of 
dlopen:

  mwette$ cat z2.c
  #include <stdio.h>
  #include <dlfcn.h>

  int main() {
    void *p;

    p = dlopen("/usr/lib/x86_64-linux-gnu/libm.so", RTLD_NOW);
    printf("%p\n", p);
  }
  mwette$ gcc z2.c -ldl
  mwette$ ./a.out
  (nil)


Matt

On 10/3/19 6:10 PM, Matt Wette wrote:
> $ guild compile-ffi gsl-sort.ffi
> ...
> ERROR: In procedure dynamic-link:
> In procedure dynamic-link: file: "libm", message: "file not found"
>
> So for some reason the linker is not finding libm.so on my Unbuntu.
> I will need to look into that.