VMS Help System Services, $CREATE GPFILE (Alpha Only)  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    On Alpha systems, creates a permanent global page file section to
    which processes can map.

    This service accepts 64-bit addresses.

    Format

      SYS$CREATE_GPFILE  gs_name_64 ,ident_64 ,prot ,length_64

                         ,acmode ,flags

    C Prototype

      int sys$create_gpfile  (void *gs_name_64, struct _secid

                             *ident_64, unsigned int prot, unsigned

                             __int64 length_64, unsigned int acmode,

                             unsigned int flags);

1 - Arguments

 gs_name_64

    OpenVMS usage:section_name
    type:         character-coded text string
    access:       read only
    mechanism:    by 32- or 64-bit descriptor-fixed-length string
                  descriptor
    Name of the global section. The gs_name_64 argument is the 32-
    or 64-bit virtual address of a naturally aligned 32- or 64-bit
    string descriptor pointing to this name string.

 ident_64

    OpenVMS usage:section_id
    type:         quadword (unsigned)
    access:       read only
    mechanism:    by 32- or 64-bit reference
    Identification value specifying the version number of a global
    section. The ident_64 argument is a quadword containing three
    fields. The ident_64 argument is the 32- or 64-bit virtual
    address of a naturally aligned quadword that contains the
    identification value.

    The first longword specifies the matching criteria in its low-
    order 2 bits. Their meanings are as follows:

           Symbolic
    Value  Name           Match Criteria

    0      SEC$K_MATALL   Match all versions of the section.
    1      SEC$K_MATEQU   Match only if major and minor
                          identifications match.
    2      SEC$K_MATLEQ   Match if the major identifications are
                          equal and the minor identification of the
                          mapper is less than or equal to the minor
                          identification of the global section.

    If you specify the ident_64 argument as 0, the version number and
    match control fields default to 0.

    The version number is in the second longword. The version number
    contains two fields: a minor identification in the low-order 24
    bits and a major identification in the high-order 8 bits. You
    can assign values for these fields by installation convention to
    differentiate versions of global sections. If no version number
    is specified when a section is created, processes that specify a
    version number when mapping cannot access the global section.

 prot

    OpenVMS usage:file_protection
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Protection to be applied to the global page file section. The
    mask contains four 4-bit fields. Bits are read from right to left
    in each field.

    Refer to the OpenVMS System Services Reference Manual to view the
    diagram depicting the mask.

    Cleared bits indicate that read, write, execute, and delete
    access, in that order, are granted to the particular category
    of user. Only read, write, and execute access are meaningful for
    section protection. Delete access bits are ignored. Read access
    also grants execute access for those situations where execute
    access applies. If 0 is specified, read access and write access
    are granted to all users.

 length_64

    OpenVMS usage:byte count
    type:         quadword (unsigned)
    access:       read only
    mechanism:    by value
    Length, in bytes, of the global page file section to be created.
    The length_64 argument must be specified as a multiple of the
    CPU-specific page size. A length of 0 cannot be specified.

 acmode

    OpenVMS usage:access_mode
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Access mode that is to be the owner of the pages created during
    the mapping. The acmode argument is a longword containing the
    access mode.

    The $PSLDEF macro in STARLET.MLB and the file PSLDEF.H in
    SYS$STARLET_C.TLB define the following symbols and their values
    for the four access modes:

    Value      Symbolic Name      Access Mode

    0          PSL$C_KERNEL       Kernel
    1          PSL$C_EXEC         Executive
    2          PSL$C_SUPER        Supervisor
    3          PSL$C_USER         User

 flags

    OpenVMS usage:mask_longword
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Flag mask specifying the type of global section to be created as
    well as its characteristics. The flags argument is a longword bit
    vector in which each bit corresponds to a flag. The $SECDEF macro
    and the SECDEF.H file define a symbolic name for each flag. You
    construct the flags argument by performing a logical OR operation
    on the symbol names for all desired flags.

    The following table describes the flags that are valid for the
    $CREATE_GPFILE service:

    Flag          Description

    SEC$M_DZRO    Pages are demand-zero pages.
    SEC$M_GBL     Pages form a global section. By default, this flag
                  is always present in this service and cannot be
                  disabled.
    SEC$M_PAGFIL  Pages form a global page-file section. SEC$M_PAGFIL
                  also implies SEC$M_WRT and SEC$M_DZRO. By default,
                  this flag is always present in this service and
                  cannot be disabled.
    SEC$M_PERM    Global section is permanent. By default, this flag
                  is always present in this service and cannot be
                  disabled.
    SEC$M_SYSGBL  Pages form a system global section. By default,
                  pages form a group global section.
    SEC$M_WRT     Pages form a read/write section. By default, this
                  flag is always present in this service and cannot
                  be disabled.

    All other bits in the flags argument are reserved for future
    use by Compaq and should be specified as 0. The condition value
    SS$_IVSECFLG is returned if any undefined bits are set.