Rockwell Automation 1771-DMC_DMC1_DMC4_DXPS Control Coprocessor User Manual - Manual (Page 231)

API Library of Routines
Appendix B
MSG_TST_MASK
B-100
Tests the bit associated with the specified message number.
C Syntax
#include
status = MSG_TST_MASK (mask,msg_num)
unsigned *mask;
unsigned msg_num;
Parameters
mask
Address of the read or write mask used with the MSG_WAIT function.
This function will test the bit corresponding to the message number.
msg_num
Number of the PLC-5 programmable-controller message (0-31).
Returns
Value Meaning
1
0 Returns 1 if the corresponding bit is set
Returns 0 if the corresponding bit is reset or msg_num is not 0Ć31
Description
Use the MSG_TST_MASK function to test bits in the message
read/write masks.
C Example
See MSG_WAIT on page B-102 for a complete example of asynchronous
message processing.
MSG_TST_MASK