All the SNA IMF intrinsics except VERS3270 return a code in the result parameter. Your program should always check the result parameter after it calls an intrinsic. A result parameter value of zero indicates that the intrinsic
executed successfully.
You might want to check for specific non-zero result values after certain intrinsic calls. The result values that each intrinsic can return are listed in
the intrinsic descriptions in Chapter 3 “Intrinsics Used with Standard MPE
I/O” and Chapter 4 “Intrinsics Used with No-Wait I/O” If any non-zero result values are important to your program, check for them
after the result parameter is returned.
For example, the RECV3270 intrinsic returns result = 24 if the receive timer expires before the host sends
data. If your program calls RECV3270 and receives result = 24, it knows that the internal screen image has not been
updated, and there is no new data from the host. Your program should
specifically check whether result = 24 after a call to RECV3270 before it calls any intrinsics that read data
from the internal screen image.
If the result parameter returns a value that has no meaning at the current
point in your program, regard it as an error and branch to your error
handling routine.
See Appendix F “Sample Programs” for examples of error checking and
error handling using the result parameter.
