None.
Allows user-written procedures to be called instead of XL Fortran intrinsics.
Not applicable.
The procedure names are treated as if they appear in an EXTERNAL statement in each compilation unit being compiled. If any of your procedure names conflict with XL Fortran intrinsic procedures, use this option to call the procedures in the source code instead of the intrinsic ones.
Because of the many Fortran 90 and Fortran 95 intrinsic functions and subroutines, you might need to use this option even if you did not need it for FORTRAN 77 programs.
SUBROUTINE GETENV(VAR)
CHARACTER(10) VAR
PRINT *,VAR
END
CALL GETENV('USER')
END
Compiling this program with no options fails because the call to GETENV is actually calling the intrinsic subroutine, not the subroutine defined in the program. Compiling with -qextern=getenv allows the program to be compiled and run successfully.