sdb(1) - f39

1SDB(1)                          CSNOBOL4 Manual                         SDB(1)
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NAME

6       sdb - SNOBOL4 debugger
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SYNOPSIS

9       sdb [ options ... ] program.sno
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DESCRIPTION

12       sdb is a debugger for snobol4(1) programs, in the mold (clawning fone)
13       of gdb(1), The GNU debugger.  sdb(1) uses readline(3) for command line
14       editing/history when available.
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16   Commands
17       break LABEL_OR_STATEMENT_NUMBER
18           Set a breakpoint.
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20       bt
21           Display call stack back trace.
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23       commands BREAKPOINT_NUMBER
24           Add sdb commands to execute (ie; print & continue) to a breakpoint.
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26       condition BREAKPOINT_NUMBER [ EXPR ]
27           If EXPR is supplied, it is used as a predicate to make the
28           breakpoint conditional, if no EXPR is supplied, any previous
29           condition is removed.
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31       continue [ COUNT ]
32           Continue from breakpoint.  The optional count specifies how many
33           times to continue past this breakpoint (sets ignore count).
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35       delete [ BREAKPOINT_NUMBER ]
36           Delete a single breakpoint, or all breakpoints.
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38       disable [ BREAKPOINT_NUMBER ]
39           Temporarily disable a breakpoint, or all breakpoints.
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41       enable [ BREAKPOINT_NUMBER ]
42           Re-enable a breakpoint, or all breakpoints.
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44       finish
45           Resume debugging after current function returns.  Will display
46           function return type and value, if any.
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48       help
49           Display help.
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51       ignore BREAKPOINT_NUMBER [ COUNT ]
52           Set (or clear) breakpoint ignore count.
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54       info
55           Display list of breakpoints and their status.
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57       list [ LABEL_OR_STATEMENT_NUMBER ]
58           Display source code.
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60       next [ COUNT ]
61           Single step execution, skipping over function calls.
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63       print EXPRESSION
64           Evaluate expression and print result.  Can be used to call
65           functions, or set variables.
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67       quit
68           Exit debugger.
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70       run
71           Restart program (works by saving breakpoints and restarting
72           snobol4).  New in version 2.1, some restrictions may apply.
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74       save FILENAME
75           Save breakpoints to file.
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77       source FILENAME
78           Read sdb commands from file.
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80       step [ COUNT ]
81           Single step.
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83       watch VARIABLE
84           Set watchpoint on a variable (break when value changes).
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86       what EXPRESSION
87           Display the datatype of expression.
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89       where
90           An alias for bt.
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92       A blank line repeats the previous command.
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94       Non-ambiguous abbreviations of commands can be used (ie; s, n).
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96       The GNU Readline library (when available) will be used for sdb(1) input
97       for command editing and history.
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99       The keyboard interrupt character (eg; Control-C) will stop a running
100       program and return control to the sdb(1) command prompt.
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102       If your program calls the SDB() function, it will act as a breakpoint.
103       You can check whether sdb(1) is loaded with the FUNCTION() predicate,
104       ie;
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106                   FUNCTION('SDB') SDB()
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FILES

109       ~/.sdbinit
110           initial command file, read on startup.
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112       .sdb_history
113           saved command history
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115       /tmp/sdb_listing.pid
116           temporary listing file for sdb.sno to read
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118       /tmp/sdb_bkpts.pid
119           temporary breakpoint save file for "run" command
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AUTHOR

125       Philip L. Budne
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127       Inspired by Fred Weigel's DDT.SNO and SITBOL's SNODDT.
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LIMITATIONS

130       sdb(1) uses a wide variety of system facilities and will interact
131       poorly with any programs that use any number of features, including:
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133       •      Altering listing settings with directive/control lines.
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135       •      Altering &STLIMIT, &ERRLIMIT, or &TRACE.
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137       •      Calling SETEXIT()
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BUGS

140       If you try to put a breakpoint on a label or line with no code or goto
141       fields, the breakpoint will never be triggered.
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143       You cannot put a breakpoint on the END label (however control always
144       returns to sdb when the END label is reached).
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146       Interrupt character trapping is in it's infancy, and only occurs at the
147       start of a each statement executed.
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149       The interrupt character is silently ignored when at the sdb command
150       prompt.
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152       Leaves an unprotected listing file of the sources in the /tmp directory
153       (create a protected directory?).
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155       “quit” and “run” commands say program is running even if first line of
156       the program has not yet been executed!
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158       Some fatal errors cannot be trapped, and sdb will be terminated.
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162CSNOBOL4B 2.3.1                 March 31, 2022                          SDB(1)