SSTEP monitor command SSTEP monitor command Syntax SSTEP task Function Execute a single step or an entire subroutine of a control program. Usage Considerations SSTEP can be used to single-step any of the available system program tasks, independent of the execution status of other system tasks. When using the program debugger, you can press CTRL+Z to generate an SSTEP command for the task being debugged. (See the eV+ Language User's Guide for details.) Parameter task Optional integer number that specifies which system program task is to be executed. If no task number is specified: task number 0 is assumed.
Details If the next program step to be executed is not a CALL, CALLP, or CALLS instruction, the SSTEP command is identical to an XSTEP command without program arguments. (See the description of the XSTEP command for more information on single-step execution of a program.) If the program step to be executed is a CALL, CALLP, or CALLS instruction, the SSTEP command causes the entire called subroutine to be executed before program execution stops at the step following the CALL, CALLP, or CALLS instruction.
(The name "SSTEP" indicates "Subroutine STEP".) As with the PROCEED and RETRY commands, an SSTEP command can be executed only after single-step execution of the preceding program instruction, a PAUSE instruction, a breakpoint, or a nonfatal error during program execution. During single-step execution, the next instruction to be executed is displayed on the system terminal and the manual control pendant. See the description of the XSTEP command for more information on single-step execution.
The SSTEP status is remembered by the system even if program execution stops within the called subroutine and is restarted at that point with additional XSTEP or SSTEP commands, or even with a PROCEED command. That is, program execution will stop when the original subroutine finally executes a RETURN instruction. eV+Operating System Reference Guide, 2.x,18321-000 Rev A Page 159