plssym - Set symbol size
This sets up the size of all subsequent symbols drawn by plpoin(3plplot) and plsym(3plplot). The actual height of a symbol is the product of the default symbol size and a scaling factor as for the character height.
Redacted form: plssym(def, scale)
This function is used in example 29.
Many developers (who are credited at http://plplot.org/credits.php) have contributed to PLplot over its long history.
PLplot documentation at http://plplot.org/documentation.php.