The features described in this topic are obsolete
and should not be used in new IDL code.

Backwards Compatibility

Avoid using obsolete routines when writing new IDL code. As IDL continues to evolve, the likelihood that obsolete routines will no longer function as expected increases. While we will continue to make every effort to ensure that obsolete routines shipped with IDL function, in a small number of cases this may not be possible.

IDL Internal Routines

Routines that are built into the IDL executable—routines not written in the IDL language—will either continue to be included in the executable until the scheduled removal release or will be re-implemented in the IDL language. In the latter case, obsolete routines may run slower than the original version. Note that obsolete routines that have been re-implemented in the IDL language may also be scheduled for eventual removal.

Routines Written in IDL

Routines written in the IDL language (.pro files) are contained in the obsolete subdirectory of the lib directory of the IDL distribution. As long as a given obsolete routine is included in this subdirectory, it will continue to function as always.