SDB

sdb − SNOBOL4 debugger

sdb program.sno

sdb is a debugger for snobol4(1) programs, in the mold (fawning clone) of gdb(1), The GNU debugger. sdb uses readline(3) for command line editing/history when available.

Commands:

break LABEL_OR_STATEMENT_NUMBER

Set a breakpoint

bt

Display call stack backtrace.

commands BREAKPOINT_NUMBER

Add sdb commands to execute (ie; print & continue) to a breakpoint.

condition BREAKPOINT_NUMBER EXPR

If EXPR is supplied, it is used as a predicate to make the breakpoint conditional.

continue EMPTY_OR_COUNT

Continue from breakpoint. The optional count specifies how many times to continue past this breakpoint (sets "ignore" count).

delete BREAKPOINT_NUMBER_OR_EMPTY

Delete a single breakpoint, or all breakpoints.

disable BREAKPOINT_NUMBER_OR_EMPTY

Temporarily disable a breakpoint, or all breakpoints.

enable BREAKPOINT_NUMBER_OR_EMPTY

Reenable a breakpoint, or all breakpoints.

finish

Resume debugging after current function returns.

help

Display help.

ignore BREAKPOINT_NUMBER COUNT

Set breakpoint ignore count.

info

Display list of breakpoints and their status.

list EMPTY_OR_STATEMENT_NUMBER

Display source code.

next EMPTY_OR_COUNT

Single step execution, skipping over function calls.

print EXPRESSION

Evaluate expression and print result. Can be used to call functions, or set variables.

quit

Exit debugger.

step EMPTY_OR_COUNT

Single step.

watch VARIABLE

Set watchpoint on a variable (break when value changes).

where

An alias for bt.

A blank line repeats the previous command.

Non-ambiguous abbreviations of commands can be used (ie; "s", "n").

The GNU Readline library (when available) will be used for sdb input for command editing and history.

snobol4(1), gdb(1), readline(3), snobol4readline(3)

Philip L. Budne

with techniques cribbed from someone’s DDT.SNO

Cannot put a breakpoint on END label.

Cannot pass arbitrary flags and arguments on the command line.