FORTRAN Reference Manual

Program Compilation
FORTRAN Reference Manual—528615-001
9-25
User Library Alternatives for Utility Subprograms
User Library Alternatives for Utility
Subprograms
The user library feature of the operating system is a convenient way to make packages
of general-utility subprograms available to multiple application programs. Alternative
methods are:
•
Use the SEARCH directive when you compile the application programs, causing
each application program’s object file to include its own copy of the utility
subprograms that it needs. The disadvantages with SEARCH are that the
application program object files are larger than they should be, and bug fixes and
other improvements to the utility subprograms are not propagated into all of
application programs unless they are re-compiled or at least re-bound.
•
Use SYSGEN to incorporate the subprogram package into the system library code
space. The disadvantage with SYSGEN is that you must request your system
manager to do this.
For more information on libraries, see the LIBRARY compiler directive in Section 10,
Compiler Directives, and the FORTRAN RUN command in Section 11, Running and
Debugging Programs.
Sample Programs Using the Search Directive
This section contains two sample programs. One shows development of a program
using SEARCH and SOURCE directives for subprograms. It also includes an
alternative development cycle using the interactive Binder.
The second program uses SEARCH to select certain subroutines from an object file of
subroutines, some of which also contain subprogram calls. (The calls can be recursive
or call other subroutines.) It shows how different users can use a subroutine object file
as a common resource.
Using the SEARCH Directive—Sample Program 1
This sample program transposes the rows and columns of a five-row, five-column
matrix named ARRAY. The steps in the development of the program are flexible. That
is, coding and compilation can take place in different sequences. However, use of the
SEARCH directive is effective only if compiled code is available to satisfy external
references; this implies that you cannot use SEARCH from a subprogram for a main
program unit.
1. Code and compile separately a subroutine subprogram that is named
PRINTARRAY. The resulting code and data blocks are in an object file named
PRINTO. (The source file name is PRINTS.)
2. Code a dummy for the transpose subroutine, TRANSPOSE. The source file name
is DUMMYS. The dummy subroutine allows program testing to occur in stages.