Experimental Physics and
Industrial Control System

On Nov 30, 2020, at 10:54 AM, Daykin, Evan via Tech-talk <tech-talk at aps.anl.gov> wrote:

What is the correct method of outputting debug information to the IOC shell from an aSub Record? We have tried errlogprintf(), printf(), and std::cout after setting eltc(1) and errLogInit in the IOC shell, but nothing seems to work. Am I missing a step?

Unless your startup script or some other software is redirecting the IOC’s stdout and/or stderr streams elsewhere a regular printf() or fprintf(stderr) should send output to the console without doing anything special.

All recent versions of Base provide a header file epicsStdio.h which redefines the keywords stdin, stdout and stderr and the routines printf(), puts() and putchar() so the iocsh stream redirection works with any code that includes this header; the redirection streams are thread-specific though, each thread has its own set of FILE* pointers and unless some code running in a thread has explicitly called say epicsSetThreadStdout() the output from printf() will still go to the main process stdout stream. If your code doesn’t explicitly include epicsStdio.h this will not affect you (no other EPICS Base headers pull in that file).

It sounds like there may be something else going on in your case, you’ll have to provide more information if you want help. Are you sure your aSub is actually being processed? Have you tried setting TPRO to confirm that?

- Andrew