intro_pxf(3F)

NAME
     INTRO_PXF  - Introduction to PXF POSIX library

IMPLEMENTATION
     See individual man pages for implementation details

DESCRIPTION
      The POSIX FORTRAN 77 Language Interfaces Standard IEEE Std 1003.9-
     1992 (POSIX.a) defines a standardized interface for accessing the
     system services of IEEE Std 1003.1-1990 (POSIX.1), and supports
     routines to access constructs not directly accessible with FORTRAN 77.

     Only a subset of the routines described in this standard are currently
     available on Cray Research systems.  For some routines, only a portion
     of the functionality described by the standard is currently
     implemented.

     Many of the service interfaces defined in POSIX.1 require the use of
     aggregate data types (for example, structures) that do not map to
     FORTRAN 77 entities.  POSIX.9 solves this problem by the use of data
     abstraction; by using additional subroutines to access and manipulate
     the aggregate data, the underlying data structures are hidden from the
     user.  It is the responsibility of the Fortran programmer to maintain
     variables corresponding to the individual components of the actual
     implementation of the aggregate data, but the programmer does not need
     to know the details of the actual implementation of the aggregate.
     The basic model of this data abstraction is as follows:

     * The programmer calls the PXFSTRUCTCREATE subroutine to "create" an
       instance of the desired aggregate data type; this subroutine returns
       a handle that the programmer subsequently uses in order to reference
       and/or manipulate the data.

     * The programmer uses additional subroutines to load values into, or
       extract values out of, the aggregate data.  These subroutines are
       passed the handle of the desired aggregate and the name of the
       specific component that is to be accessed.  The programmer has
       direct control over only one component at a time.

     * If an application passes information to the system, the PXFtypeSET
       subroutine is called once for each member before calling the system
       procedure.  Currently, only PXFINTSET and PXFSTRSET are implemented.

     * If an application needs to get information from the system, the
       PXFtypeGET subroutine is called once for each member after calling
       the system procedure.  Currently, only PXFINTGET and PXFINTSET are
       implemented.

     * When an instance of an aggregate is no longer required, a subroutine
       (PXFSTRUCTFREE) can be called to release it.

     * When calling the actual system procedure, the calling sequence is
       equivalent to the C binding as shown in POSIX.1, except that a
       handle is used in place of the POSIX.1 structure (pointer) argument.

   Classification of routines
     The POSIX routines can be divided into several general groups:

     * Process primitives

        - Routines that create, execute, or terminate a process (such as
          PXFFORK(3F))

        - Signal routines (not available at this time)

     * Process environment routines

        - Process identification routines (such as PXFGETPID)

        - User identification routines (such as PXFSETUID)

        - Process groups routines (such as PXFGETGRP)

        - System identification routines (PXFUNAME)

        - Time routines (PXFTIME and PXFTIMES)

        - Environment variable processing routines (such as PXFGETENV)

        - Terminal identification routines (such as PXFCTERMID)

        - Configurable system values (such as PXFSYSCONF)

     * File and directory routines (such as PXFCREAT and PXFISCHR)

     * Input and output primitives (not available at this time)

     * Device and class-specific procedures (not available at this time)

     * Fortran intrinsics (not available at this time)

     See the individual man pages for complete details.

SEE ALSO
     Application Programmer's Library Reference Manual, publication
     SR-2165, for the printed version of this man page.