EMSG

#emsg := EMSG errorCode

or

EMSG tableItem

The EMSG command will return a string describing the meaning of the numerical error code errorCode returned by an STx command. If a table item (tableItem) is passed instead of an error code, all error descriptions are stored in the table (deleting the previous contents).

// store all error messages in a simple table
#tab := new table *
EMSG $#tab

// show this table to the user
showitem $#tab

// tidily dispose of the table after use
delete /Var #tab

or

// check if command fails and display error message on error
#spu := new spu * testspu pa pb pc
if '$rc' > 0 em $rc ; SPU creation failed: $(emsg $rc)