-alarm¶

Introduction¶

The -alarm N option terminates wgrib2 after N seconds (real time). For example, you may want to use -alarm to kill a wgrib2 job that running too long on a web server (ex. grib_filter).

The code for -alarm is SVr4, BSD, POSIX-1-2001 and IEEE Std 1003.1-2001 compatible. The code is also supported by the Cygwin system for Windows systems. The -alarm will need to be disabled in the makefile for non-compatible systems. (Change DISABLE_ALARM=0 to DISABLE_ALARM=1 in the makefile.)

The current version of -alarm simply terminates the process. This may be the appropriate action when wgrib2 is taking too long. However, this heavy-handed action may not be an ideal action for programs that are calling the wgrib2 subroutine. For these situations, the alarm should be set up by the main program so that a more appropriate action can be taken.

The -alarm option is a replacement for -limit which limits the number of (sub)messages which are processed. Jobs on web servers may hang because of problems with the network connections which will never trigger the -limit option.

Usage¶

-alarm N
          N is an integer from 0..65536 (ISO C standard)
          N = 0 will remove any pending alarm

The -alarm option is a setup/init option. So the alarm is activated in the setup phase, cannot altered in the data processing phase and is not removed the finalize phase. (wgrib2 v2.0.8+ will remove the alarm in the finalize phase.)

For Posix systems, the system generates a SIGALRM signal to the process after N seconds. The default action is to terminate the process (wgrib2).