Before using pgtcl commands, you must load
libpgtcl into your Tcl application. This is normally
done with the Tcl load command. Here is an example:
load libpgtcl[info sharedlibextension]
The use of info sharedlibextension is recommended in
preference to hard-wiring .so or .sl into
the program.
The load command will fail unless the system's dynamic
loader knows where to look for the libpgtcl shared
library file. You may need to work with ldconfig, or
set the environment variable LD_LIBRARY_PATH, or use
some equivalent facility for your platform to make it work. Refer
to the PostgreSQL installation instructions for
more information.
libpgtcl in turn depends on libpq, so the
dynamic loader must also be able to find the libpq shared
library. In practice this is seldom an issue, since both of these
shared libraries are normally stored in the same directory, but it
can be a stumbling block in some configurations.
If you use a custom executable for your application, you might choose
to statically bind libpgtcl into the executable and thereby
avoid the load command and the potential problems of dynamic
linking. See the source code for pgtclsh for an example.