──TRACE(─┬────────┬─)─────
└─option─┘
TRACE returns trace actions currently in effect.
If option is supplied, it must be the valid prefix (?), one of the alphabetic character options (that is, starting with A, C, E, F, I, L, N, O, or R) associated with the TRACE instruction, or both. The function uses option to alter the effective trace action (such as tracing labels). Unlike the TRACE instruction, the TRACE function alters the trace action even if interactive debug is active.
Unlike the TRACE instruction, option cannot be a number.
Here are some examples:
TRACE() -> '?R' /* maybe */
TRACE('O') -> '?R' /* also sets tracing off */
TRACE('?I') -> 'O' /* now in interactive debug */