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On Jan 22, 2021, at 7:11 PM, Guy Harris via tcpdump-workers 
<tcpdump-workers@lists.tcpdump.org> wrote:

> I'll try experimenting with one of my Ubuntu VMs.

Welcome to Shared Library Search Hell.

Most UN*Xes have a notion of RPATH (with, of course, different compiler 
command-line flags to set it).

pcap-config provides one if the shared library isn't going to be installed in 

The pkg-config file doesn't provide one, however, and some searching indicates 
that the pkg-config maintainers recommend *against* doing so.  They recommend 
using libtool when linking, instead.  Part of the problem here may be that 
setting the RPATH in an executable affects how it searches for *all* libraries, 
so it could affect which version of an unrelated library is found.

(The existence of libtool is an indication that shared libraries have gotten 
messy on UN*X.)

Perhaps for this particular case the right thing to do is to set 
LD_LIBRARY_PATH when running the temporarily-installed tcpdump.

The macOS linker appears to put absolute paths for shared libraries into the 
executable by default:

        $ otool -L /bin/cat
                /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, 
current version 1281.100.1)

so this may not be an issue there.

(Also, the existence of the term "DLL hell" is an indication that shared 
libraries have gotten messy on Windows, but I digress.... :-))

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