## controlling ploticus from other programs (automation) | Welcome Gallery Handbook |
| Manual page for controlling_ploticus_from_other_programs_(automation)(PL)

## DESCRIPTION

Notes on executing ploticus under the control of another program in an automated way.``

## STRATEGY

As of version 2.00, pl can be directly invoked as a CGI program

A perl script which implements a web interface to ploticus was contributed by Tom McClure.``

Since it is a command-line program, ploticus can easily be invoked by other programs automatically for unattended use.`` For instance, web server CGI scripts can invoke pl to build PNG or GIF data displays on demand. Or, cron could invoke pltab to generate and print tables at specified times.``

The invoking program can build a ploticus script on the fly, or use one that has been created in advance.``

The actual invocation can be done using the equivalent of `system()`. For example, in C:

  `system( "pl -gif myfile.p ITEM=hgxz" );`

## VARIABLES

Variables may be useful for implementation of changeable paramters (the invoking program would execute pl or pltab, and set variables on the command line).`` For example:

`pl -gif status.p STARTDATE=010198 ENDDATE=062699 GROUP=hgc`
data display engine
Copyright Steve Grubb

Markup created by unroff 1.0, `` `` August 23, 2001.