NET/MASTER Network Control Language (NCL) Reference Manual

EMSREAD
Verbs
3–62 106126 Tandem Computers Incorporated
WAIT
specifies what NCL is to do if no message has arrived.
NO
specifies that if no message has arrived, control is to return to the EMSPROC
NCL process immediately with all specified variables (if any) set to null values
and the &SYS.RETCODE system variable set to 12.
YES
specifies that the EMSPROC NCL process is to be suspended until a message
arrives.
nnnn
specifies the number of seconds that the EMSPROC NCL process is to be
suspended for, while waiting for a message to arrive. If no message arrives,
NCL sets the &SYS.RETCODE system variable to 12. After this time interval,
control is returned to the process. WAIT=0 (zero) has the same effect as
WAIT=NO.
Considerations
For the interpretation of Message Profile Variables contained in MDOs, see
Section 7, “Message Profile Variables.”
When EMSREAD reads a message, EMSPROC creates an MDO variable (mapped
by $MSG) with the stem &$EMS., and places the text and the attributes of the
message, such as color and intensity, into the MDO. This MDO variable also
contains a copy of all EMS tokens. On completion of the EMSREAD verb, and if
parsing is specified, the &SYS.VARCNT system variable is set to the number of
variables created or modified by the operation.
See INTREAD, LOGREAD, and MSGREAD, which also automatically create MDO
variables mapped by $MSG. For more information on MDO variables, refer to the
NonStop NET/MASTER NCL Programmer's Guide.
When EMSREAD completes successfully, the variable &$EMS.CNM. may contain
a CNM record, either generated by CNMALERT or sent from ISR. You can
analyze the contents of this MDO variable using the NCL verb CNMVECTR.
The &SYS.RETCODE system variable is set to 0 (zero) by EMSREAD, except when
WAIT=NO or WAIT= nnnn was coded and no message arrived. In this case NCL
sets the &SYS.RETCODE system variable to 12. These (0 and 12) are the only
return codes.
NCL sets the &SYS.LOOPCTL system variable to 1000 each time the EMSREAD
verb is executed, unless the user explicitly sets it to 0 (zero).