Associates a named common event flag cluster with a process
to execute the current image and to be assigned a process-
local cluster number for use with other event flag services.
If the named cluster does not exist but the process has suitable
privilege, the service creates the cluster.
Format
SYS$ASCEFC efn ,name ,[prot] ,[perm]
C Prototype
int sys$ascefc (unsigned int efn, void *name, char prot, char
perm);
1 – Arguments
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.