SDB(1) CSNOBOL4 Manual SDB(1)NAMEsdb - SNOBOL4 debugger
SYNOPSISsdb [ options ... ] program.sno
DESCRIPTIONsdb is a debugger for snobol4(1) programs, in the mold (clawning fone)
of gdb(1), The GNU debugger. sdb(1) uses readline(3) for command line
editing/history when available.
Commands
break LABEL_OR_STATEMENT_NUMBER
Set a breakpoint.
bt Display call stack back trace.
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, if no EXPR is supplied, any previous
condition is removed.
continue [ COUNT ]
Continue from breakpoint. The optional count specifies how many
times to continue past this breakpoint (sets ignore count).
delete [ BREAKPOINT_NUMBER ]
Delete a single breakpoint, or all breakpoints.
disable [ BREAKPOINT_NUMBER ]
Temporarily disable a breakpoint, or all breakpoints.
enable [ BREAKPOINT_NUMBER ]
Re-enable a breakpoint, or all breakpoints.
finish
Resume debugging after current function returns. Will display
function return type and value, if any.
help
Display help.
ignore BREAKPOINT_NUMBER [ COUNT ]
Set (or clear) breakpoint ignore count.
info
Display list of breakpoints and their status.
list [ STATEMENT_NUMBER ]
Display source code.
next [ 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 [ COUNT ]
Single step.
watch VARIABLE
Set watchpoint on a variable (break when value changes).
what
Display the datatype of variable contents (or expression).
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(1) input
for command editing and history.
The keyboard interrupt character (eg; Control-C) will stop a running
program and return control to the sdb(1) command prompt.
If your program calls the SDB() function, it will act as a breakpoint.
You can check whether sdb(1) is loaded with the FUNCTION() predicate,
ie;
FUNCTION('SDB') SDB()SEE ALSOsnobol4(1), gdb(1), readline(3), snobol4readline(3)AUTHOR
Philip L. Budne
Inspired by Fred Weigel's DDT.SNO and SITBOL's SNODDT.
LIMITATIONSsdb(1) uses a wide variety of system facilities and will interact
poorly with any programs that use any number of features, including:
· Altering listing settings with directive/control lines.
· Altering &STLIMIT, &ERRLIMIT, or &TRACE.
· Calling SETEXIT()BUGS
If you try to put a breakpoint on a label or line with no code or goto
fields, the breakpoint will never be triggered.
You cannot put a breakpoint on the END label (however control always
returns to sdb when the END label is reached).
There is no “run” command; you cannot restart the program without
quitting and losing breakpoint settings.
Interrupt character trapping is in it's infancy, and only occurs at the
start of a each statement executed.
The interrupt character is silently ignored when at the sdb command
prompt.
sdb does not read an init file (ie; .sdbinit).
CSNOBOL4B 2.0 January 1, 2015 SDB(1)
