vThe status of DO loops and other structures: Executing a SIGNAL while within a subroutine is safe
because DO loops, and so forth, that were active when the subroutine was called are not ended. (But
those currently active within the subroutine are ended.)
vTrace action: After a subroutine is debugged, you can insert a TRACE Offat the beginning of it, and
this does not affect the tracing of the caller. Conversely,if you simply wish to debug a subroutine, you
can insert a TRACE Results at the start and tracing is automatically restored to the conditions at entry
(for example, Off) upon return. Similarly, ?(interactive debug) and !(command inhibition) are saved
across routines.
vNUMERIC settings: The DIGITS, FUZZ, and FORM of arithmetic operations (in section “NUMERIC” on
page 150) are saved and then restored on return. A subroutine can, therefore, set the precision, and so
forth, that it needs to use without affecting the caller.
vADDRESS settings: The current and previous destinations for commands (see section “ADDRESS” on
page 132) are saved and then restored on return.
vCondition traps: (CALL ON and SIGNAL ON) are saved and then restored on return. This means that
CALL ON, CALL OFF,SIGNAL ON, and SIGNAL OFF can be used in a subroutine without affecting the
conditions the caller set up.
vCondition information: This information describes the state and origin of the current trapped condition.
The CONDITION built-in function returns this information. See section “CONDITION” on page 178.
vElapsed-time clocks: A subroutine inherits the elapsed-time clock from its caller (see section “TIME” on
page 193), but because the time clock is saved across routine calls, a subroutine or internal function
can independently restart and use the clock without affecting its caller. For the same reason, a clock
started within an internal routine is not available to the caller.
vOPTIONS settings: ETMODE and EXMODE are saved and then restored on return. For more
information, see section “OPTIONS” on page 151.
Implementation maximum: The total nesting of control structures, which includes internal routine calls, is
dependent upon available storage.
CALL
Chapter 13. Keyword Instructions 137