<para>

In <productname>PostgreSQL</productname>, the same function name can be used for

different function definitions as long as the number of arguments or their types

different function definitions if the functions are placed in different

schemas, or if the number of arguments or their types

differ. Tcl, however, requires all procedure names to be distinct.

PL/Tcl deals with this by making the internal Tcl procedure names contain

the object

ID of the function from the system table <structname>pg_proc</structname> as part of their name. Thus,

PL/Tcl deals with this by including the argument type names in the

internal Tcl procedure name, and then appending the function's object

ID (OID) to the internal Tcl procedure name if necessary to make it

different from the names of all previously-loaded functions in the

same Tcl interpreter. Thus,

<productname>PostgreSQL</productname> functions with the same name

and different argument types will be different Tcl procedures, too. This

is not normally a concern for a PL/Tcl programmer, but it might be visible

when debugging.

</para>

<para>

For this reason among others, a PL/Tcl function cannot call another one

directly (that is, within Tcl). If you need to do that, you must go

through SQL, using <function>spi_exec</function> or a related command.

</para>

</sect1>

</chapter>