Option Arguments

Arguments  specifying options are usually of type CHARACTER*1. The meaning of each valid value is given , as in this example:

UPLO
(input) CHARACTER*1
= 'U': Upper triangle of A is stored;
= 'L': Lower triangle of A is stored.

The corresponding lower-case characters may be supplied (with the same meaning), but any other value is illegal (see subsection 5.1.8).

A longer character string can be passed as the actual argument, making the calling program more readable, but only the first character is significant; this is a standard feature of Fortran 77. For example:

       CALL SPOTRS('upper', . . . )