/sys$common/syshlp/helplib.hlb System Services, $CREATE GDZRO (Alpha Only), Arguments  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 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 the 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 demand-zero 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 demand-zero 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.

                                   NOTE

       Creating a memory-resident global section with shared page
       tables does not imply that the global section must have
       a length that is an even multiple of CPU-specific page
       table pages. The global section might not fully use the
       last shared page table page.

 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.

    If the memory-resident global section is created with shared
    page tables, this is the access mode that is stored in the owner,
    read, and write fields of the corresponding shared page table
    entries (PTEs).

    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_GDZRO service:

    Flag          Description

    SEC$M_DZRO    Pages are demand-zero pages. By default, this flag
                  is always present in this service and cannot be
                  disabled.
    SEC$M_GBL     Pages form a global section. By default, this flag
                  is always present in this service and cannot be
                  disabled.
    SEC$M_MRES    Pages form a memory-resident section. By default,
                  this flag is always present in this service and
                  cannot be disabled.
    SEC$M_PERM    Global section is permanent. By default, this flag
                  is always present in this service and cannot be
                  disabled.
    SEC$M_RAD_    When set, the argument rad_mask is used as a mask
    HINT          of RADs from which to allocate memory. See the rad_
                  mask argument description for more information.
    SEC$M_READ_   Create shared table pages for the section that
    ONLY_SHPT     allow read access only.
    SEC$M_SHMGS   Create a shared-memory global section.
    SEC$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.

 reserved_length_64

    OpenVMS usage:byte count
    type:         quadword (unsigned)
    access:       write only
    mechanism:    32- or 64-bit reference
    Length, in bytes, of the global section as currently registered
    in the Reserved Memory Registry. The reserved_length_64 argument
    is the 32- or 64-bit virtual address of a naturally aligned
    quadword into which the service returns the reserved length.

    If reserved_length_64 is not specified or is specified as 0, no
    reserved length is returned to the caller.

    If the memory-resident global section is not registered,
    reserved_length_64 is written with the value 0.

 rad_mask

    OpenVMS usage:mask_quadword
    type:         quadword (unsigned)
    access:       read only
    mechanism:    by value
    Use the rad_mask argument to specify from which RADs to allocate
    memory. Currently only one bit may be set. The specified RAD
    must contain memory. This argument is only a hint. Memory may be
    obtained from other RADs if no free memory is available at the
    time of allocation.

    The rad_mask argument is considered only if the SEC$M_RAD_HINT
    flag is specified. Otherwise, this argument is ignored.

    On a system that does not support resource affinity domains
    (RADs), specifying 1 for the rad_mask argument is allowed.

    Note: OpenVMS support for RADs is available only on the new
    AlphaServer GS series systems. For more information about using
    RADs, refer to the OpenVMS Alpha Partitioning and Galaxy Guide.