The /dlines qualifier allows a D in column 1 to be
treated like a character space. The rest of that line will then be
parsed as a normal Fortran statement. By default, KAP treats these
lines as comments. This qualifier is useful for the inclusion or
exclusion of debugging lines. Data dependence relationships may be
different when the D lines are included.
In the following example, the /nodlines default would
cause the WRITE statement to be treated as a comment:
DO 10 I = 1,N
A (I) = B (I)
D WRITE (*,*) A (I)
10 CONTINUE
But when /dlines is specified, KAP sees a WRITE
statement and will not optimize the whole loop as it is:
DO 2 I=1,N
A(I) = B(I)
2 CONTINUE
DO 3 I=1,N
WRITE (*, *) A(I)
3 CONTINUE