2.3 Compiling a Program Using the kfort Driver

The kfort command invokes a driver program that automatically calls KAP, the Digital Fortran compiler, and the linker.

• Passing default KAP qualifier settings to kfort

  Because kfort calls KAP and the Digital Fortran compiler, you can substitute the kfort command for the Fortran command. For example, to use kfort to compile myprog.f with the default KAP qualifier settings, use the command:

  kfort myprog.f
  

  The kfort command uses the KAP preprocessor on myprog.f , compiles the result with the Digital Fortran compiler, links the object code into an executable image, and produces the following files in the current directory:

  • myprog_cmp.f - the optimized source file

  • myprog.out - the annotated source file showing default KAP qualifier settings

  • myprog.obj - the object file

  • myprog.exe - an executable file

  To cause KAP to generate an executable file with a name you specify, use the /executable qualifier as follows:

  kfort /executable=my_prog
  

  my_prog.exe results.

  kfort inserts /executable in front of the first file name it sees. For example, the following command line produces one executable named file_1.exe .

  kfort /fkapargs=(/conc/ur=1) file_1.f file_2.f file_3.f
  

  To see a list of the KAP qualifiers and Digital Fortran compiler qualifiers passed by kfort , use the /verbose qualifier as follows:

  kfort /fkapargs=(/verbose) myprog.f
  

  An example of the output is as follows:

  kapf /cmp=myprog_cmp.f myprog.f               /natural
   KAP/Digital_VMS_F   V3.1 k271625 970317    04-Apr-1997   13:16:07
  0 errors in file myprog.f
  
  Issuing the compiler command:
   for/fast/optimize=(tune=host,level=5) myprog_cmp.f
  
  issuing link command:
   link /EXECUTABLE=myprog.exe myprog_cmp.obj
  

• Passing KAP qualifiers to kfort

  The /fkapargs qualifier specifies one or more KAP command qualifiers to the preprocessor. For example, to use kfort to optimize and compile the file myprog.f using KAP qualifiers for general optimization, use the command:

  kfort /fkapargs=(/optimize=5/roundoff=3/scalaropt=3/list=myprog_annotated.out) -
  myprog.f
  

  The following files result:

  • myprog_cmp.f - the optimized source file

  • myprog_annotated.out - the annotated source file renamed by the /list qualifier

  • myprog.obj - the object file

  • myprog.exe - the executable file

  For descriptions of all KAP command qualifier, see Chapter 4.

• Passing Digital Fortran compiler qualifiers to kfort

  Any command-line qualifier that is valid for the Digital Fortran compiler or the linker is valid for the kfort command. You can specify compiler qualifiers and KAP qualifiers on the same line, as follows:

  kfort /fkapargs=(/optimize=5/roundoff=3/scalaropt=3)/nowarn  myprog.f
  

  The kfort command specifies the Digital Fortran compiler qualifiers /optimize=(tune=host,level=5) , /natural , and /fast by default. To override any of the individual compiler qualifiers encompassed by /fast , specify them on the kfort command line. For example, the following command sets the compiler qualifier /math_library=accurate and overrides the default /math_library=fast set by /fast :

  kfort /math_library=accurate myprog.f
  

  For information about the /fast compiler qualifier, see the Digital Fortran User Manual.

The /optimize=(tune=host,level=5) qualifier causes the compiler to optimize to the host architecture. For example, if you want to optimize for the ev5 architecture but are compiling on an ev4 system, you should override the default setting of the /tune qualifier, as follows:

kfort  /optimize=(tune=ev4,level=4) myprog.f