This option is useful for the inclusion or exclusion of debugging lines. Use the -DD option to compile source lines containing user debugging statements.
The -DD Option
Debugging statements included in a Fortran program source are indicated by the letter D in column 1. The -DD option instructs the compiler to treat a D in column 1 of Fortran source as a space character. The rest of that line is then parsed as a normal Fortran statement.
For example, to compile any debugging statements in program prog1.f, enter the following command:
prompt>ifc -DD prog1.f
The above command causes the debugging statement
D PRINT *, "I= ",I
embedded in the prog1.f to execute and print lines designated for debugging.
By default, the compiler takes no action on these statements. In the following example, if -DD is not specified (default), the D line is ignored:
|
do 10 i = 1, n a(i) = b(i) D write (*,*) a(i) 10 continue |
But when -DD is specified, the compiler sees a write statement as if the code is:
|
do 10 i = 1, n a(i) = b(i) write (*,*) a(i) 10 continue |
The -DX and -DY Options
Two additional distinctions to compile source lines containing user debugging statements are also available with these variations of the -DD option:
-DX compiles debug statements indicated by an X or an x in column 1; if this option is not set these lines are treated as comments.
-DY compiles debug statements indicated by an Y or an y in column 1; if this option is not set these lines are treated as comments.