efn

    OpenVMS usage:ef_number
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Number of any event flag contained within the desired common
    event flag cluster. The efn argument is a longword value
    specifying this number; however, $ASCEFC uses only the low-order
    byte.

    There are two common event flag clusters: cluster 2 and cluster
    3. Cluster 2 contains event flag numbers 64 to 95, and cluster
    3 contains event flag numbers 96 to 127. (Clusters 0 and 1 are
    process-local event flag clusters.)

    To associate with common event flag cluster 2, specify any flag
    number in the cluster (64 to 95); to associate with common event
    flag cluster 3, specify any event flag number in the cluster (96
    to 127).

 name

    OpenVMS usage:ef_cluster_name
    type:         character-coded text string
    access:       read only
    mechanism:    by descriptor-fixed-length string descriptor
    Name of the common event flag cluster with which to associate.
    The name argument is the address of a character string descriptor
    pointing to this name string.

    The character string descriptor can be 1 to 15 bytes in length,
    and each byte can be any 8-bit value.

    Common event flag clusters are accessible only to processes
    having the same UIC group number, and each such process must
    associate with the cluster using the same name (specified in the
    name argument). The operating system implicitly associates the
    group UIC number with the name, making the name unique to a UIC
    group.

    You can specify any name from 1 to 43 characters. All processes
    mapping to the same global section must specify the same name.
    Note that the name is case sensitive.

    Use of characters valid in logical names is strongly encouraged.
    Valid values include alphanumeric characters, the dollar sign
    ($), and the underscore (_). If the name string begins with an
    underscore (_), the underscore is stripped and the resultant
    string is considered to be the actual name. Use of the colon (:)
    is not permitted.

    Names are first subject to a logical name translation, after
    the application of the prefix GBL$ to the name. If the result
    translates, it is used as the name of the section. If the
    resulting name does not translate, the name specified by the
    caller is used as the name of the section.

    Additional information on logical name translations and
    on section name processing is available in the VSI OpenVMS
    Programming Concepts Manual.

 prot

    OpenVMS usage:Boolean
    type:         byte (unsigned)
    access:       read only
    mechanism:    by value
    Protection specifier that allows or disallows access to the
    common event flag cluster for processes with the same UIC group
    number as the creating process. The prot argument is a longword
    value, which is interpreted as Boolean.

    The default value 0 specifies that any process with the same UIC
    group number as the creating process can access the event flag
    cluster. The value 1 specifies that only processes having the UIC
    of the creating process can access the event flag cluster.

    When the prot argument is 1, all access to the Group category is
    denied.

    The process must have associate access to access an existing
    common event flag cluster.

 perm

    OpenVMS usage:Boolean
    type:         byte (unsigned)
    access:       read only
    mechanism:    by value
    Permanent specifier that marks a common event flag cluster as
    either permanent or temporary. The perm argument is a longword
    value, which is interpreted as Boolean.

    The default value 0 specifies that the cluster is temporary. The
    value 1 specifies that the cluster is permanent.