NAME: undefine PURPOSE: effacer une variable meme chose que delvar mais utiulisable ds un programme et utilisable que pour une variable a la fois CATEGORY: CALLING SEQUENCE: UNDEFINE, varname INPUTS: varname: la variable a detruire EXAMPLE: IDL> a=1 IDL> undefine,a % Compiled module: UNDEFINE. IDL> help, a A UNDEFINED = MODIFICATION HISTORY: trouve sur la page web de D.Fanning http://www.dfanning.com : QUESTION: How do I make an IDL variable have a type "undefined"? ANSWER: At the main IDL level you can use the IDL procedure DELVAR to delete an IDL variable and make it undefined. Inside of procedures and functions, I use this little program named UNDEFINE that I got from Andrew Cool at the DSTO High Frequency Radar Division in Adelaide, Australia.