OSI/MHS Gateway Programmatic Interface (GPI) Reference Manual
Object Classes and Attribute Types
OSI/MHS Gateway Programmatic Interface (GPI) Reference Manual—522223-001
3-24
MH-C-EXTENSION
Implementation and Usage Notes
•
The correspondence between the following DDL names and the ASN.1-defined 
names in Recommendation X.411 (1988) are: 
•
OM-S-ONFILE-STRING is a value syntax that applies to messages exceeding 64 
kilobytes.
For the attribute MH-T-EXTENSION-VALUE, this value syntax is an alternative to 
OM-S-ENCODING-STRING.
When this attribute has the syntax OM-S-ONFILE-STRING, the GPI library stores 
the value in a file, and the value retains the characteristics of its primary syntax. 
For outbound messages, the client program should specify OM-S-ONFILE-STRING 
as the syntax of an attribute when the memory storage space might be insufficient to 
accommodate the value of the attribute. The client can specify this syntax for 
specific strings when the accumulated length of the strings might overflow the total 
string area specified in the max-table-data parameter of the GPI_INITIALIZE_ 
procedure call. 
For inbound messages, the Gateway Interface Process automatically specifies OM-
S-ONFILE-STRING for those strings that exceed the value in the max-table-data 
parameter of the GPI_INITIALIZE_ call or that exceed the maximum length 
specified in the max-in-memory-string-len parameter of the 
GPI_MT_START_TRANSFER_IN_ call.
Attributes that have the syntax OM-S-ONFILE-STRING are treated as long strings. 
regardless of their actual length: that is, they are treated as if they were longer than 
the specification of the max-string-len parameter of GPI_INITIALIZE_. Thus, you 
can use only the procedure calls GPI_OM_READ_ and GPI_OM-WRITE_ to read 
and write the values of strings that have the syntax OM-S-ONFILE-STRING.
GPI Name
X.411 Name
MH-T-COMMON-NAME CommonName
MH-T-EXPANSION-HISTORY DLExpansionHistory
MH-T-EXPANSION-PROHIBITED DLExpansionProhibited
MH-T-INTERNAL-TRACE-INFO InternalTraceInformation
MH-T-EXPANSION-HISTORY OriginatorAndDLExpansionHistory
MH-T-REPORTING-DL-NAME ReportingDLName
MH-T-PREFERRED-DELIVERY-MODES RequestedDeliveryMethod
MH-T-TERMINAL-TYPE TerminalType










