existvar — Apollo

10.0;existvar (exist_variable), revision 1.0, 88/01/21
existvar (exist_variable) -- Check that a variable is set.
existvar var_name [...]



DESCRIPTION
     The existvar command checks if the variable name(s) declared as its
     argument(s) has a currently set value.  If the variable is currently set,
     existvar returns a "true" value.  If the variable is not currently set,
     existvar returns "false".  If you specify more than one variable name to
     check, all the variables must exist for existvar to return "true".

ARGUMENTS
     var_name [...] (required)
                       Specify the variable name to be checked.  Multiple
                       names are permitted, separated by blanks.
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