Re: Linking against particular libssl

[Kai Ruottu <kai dot ruottu at wippies dot com>]

15.4.2014 11:37, Sahib Jakhar kirjoitti:
> Hi,
>
> We have a build machine where two versions of libssl exist (one of
> them custom built - against which we want to link). However, no matter
> what we try, it is linking against the system's libssl.

Not caring to investigate what you did "wrong", here is the usual 
practice...

There is a quite well-known solution for using custom shared libraries 
instead
of the ones provided by the system's standard C library etc.  And that 
is using
the '-rpath' option during linking to tell where the custom libraries are :

-rpath dir
Add a directory to the runtime library search path. This is used when 
linking an
ELF executable with shared objects. All `-rpath' arguments are concatenated
and passed to the runtime linker, which uses them to locate shared 
objects at
runtime. The `-rpath' option is also used when locating shared objects which
are needed by shared objects explicitly included in the link; see the 
description
of the `-rpath-link' option. If `-rpath' is not used when linking an ELF
executable, the contents of the environment variable LD_RUN_PATH will be 
used
if it is dened.

Every newbie of course also learns how to add linker options onto the 
'gcc' command
line.  Even the 'gcc --help' command will show this, no need to consult 
the nice GCC
manual.  So one uses the '-Wl, <linker_option>', replacing spaces with 
commas :

-Wl,option
   Pass option as an option to the linker. If option contains commas, 
it is split
   into multiple options at the commas.