Step-by-step guide
Easy peasy. Use the "defined" function which takes a single key name as argument. e.g.
grib_filter example
if (defined(Latin1)) { print "Key Latin1 is there for this message"; }
Easy peasy. Use the "defined" function which takes a single key name as argument. e.g.
if (defined(Latin1)) { print "Key Latin1 is there for this message"; }