1PDX(1) General Commands Manual PDX(1)
2
6 pdx - pascal debugger
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9 pdx [-r] [objfile]
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12 Pdx is a tool for source level debugging and execution of Pascal pro‐
13 grams. The objfile is an object file produced by the Pascal translator
14 pi(1). If no objfile is specified, pdx looks for a file named ``obj''
15 in the current directory. The object file contains a symbol table
16 which includes the name of the all the source files translated by pi to
17 create it. These files are available for perusal while using the
18 debugger.
19 If the file ``.pdxinit'' exists in the current directory, then the
21 debugger commands in it are executed.
22 The -r option causes the objfile to be executed immediately; if it ter‐
24 minates successfully pdx exits. Otherwise it reports the reason for
25 termination and offers the user the option of entering the debugger or
26 simply letting px continue with a traceback. If -r is not specified,
27 pdx just prompts and waits for a command.
28 The commands are:
30 run [args] [< filename] [> filename]
32 Start executing objfile, passing args as command line arguments;
33 < or > can be used to redirect input or output in the usual man‐
34 ner.
35 trace [in procedure/function] [if condition]
37 trace source-line-number [if condition]
38 trace procedure/function [in procedure/function] [if condition]
39 trace expression at source-line-number [if condition]
40 trace variable [in procedure/function] [if condition]
41 Have tracing information printed when the program is executed.
42 A number is associated with the command that is used to turn the
43 tracing off (see the delete command).
44 The first argument describes what is to be traced. If it is a
46 source-line-number, then the line is printed immediately prior
47 to being executed. Source line numbers in a file other than the
48 current one must be preceded by the name of the file and a
49 colon, e.g. ``mumble.p:17''.
50 If the argument is a procedure or function name then every time
52 it is called, information is printed telling what routine called
53 it, from what source line it was called, and what parameters
54 were passed to it. In addition, its return is noted, and if
55 it's a function then the value it is returning is also printed.
56 If the argument is an expression with an at clause then the
58 value of the expression is printed whenever the identified
59 source line is reached.
60 If the argument is a variable then the name and value of the
62 variable is printed whenever it changes. Execution is substan‐
63 tially slower during this form of tracing.
64 If no argument is specified then all source lines are printed
66 before they are executed. Execution is substantially slower
67 during this form of tracing.
68 The clause ``in procedure/function'' restricts tracing informa‐
70 tion to be printed only while executing inside the given proce‐
71 dure or function.
72 Condition is a Pascal boolean expression and is evaluated prior
74 to printing the tracing information; if it is false then the
75 information is not printed.
76 There is no restriction on the amount of information that can be
78 traced.
79 stop if condition
81 stop at source-line-number [if condition]
82 stop in procedure/function [if condition]
83 stop variable [if condition]
84 Stop execution when the given line is reached, procedure or
85 function called, variable changed, or condition true.
86 delete command-number
88 The trace or stop corresponding to the given number is removed.
89 The numbers associated with traces and stops are printed by the
90 status command.
91 status [> filename]
93 Print out the currently active trace and stop commands.
94 cont Continue execution from where it stopped. This can only be done
96 when the program was stopped by an interrupt or through use of
97 the stop command.
98 step Execute one source line.
100 next Execute up to the next source line. The difference between this
102 and step is that if the line contains a call to a procedure or
103 function the step command will stop at the beginning of that
104 block, while the next command will not.
105 print expression [, expression ...]
107 Print out the values of the Pascal expressions. Variables
108 declared in an outer block but having the same identifier as one
109 in the current block may be referenced as ``block-name . vari‐
110 able''.
111 whatis identifier
113 Print the declaration of the given identifier.
114 which identifier
116 Print the full qualification of the given identifer, i.e. the
117 outer blocks that the identifier is associated with.
118 assign variable expression
120 Assign the value of the expression to the variable.
121 call procedure(parameters)
123 Execute the object code associated with the named procedure or
124 function.
125 help Print out a synopsis of pdx commands.
127 gripe Invokes a mail program to send a message to the person in charge
129 of pdx.
130 where Print out a list of the active procedures and functions and the
132 respective source line where they are called.
133 source filename
135 Read pdx commands from the given filename. Especially useful
136 when the filename has been created by redirecting a status com‐
137 mand from an earlier debugging session.
138 dump [> filename]
140 Print the names and values of all active data.
141 list [source-line-number [, source-line-number]]
143 list procedure/function
144 List the lines in the current source file from the first line
145 number to the second inclusive. As in the editor ``$'' can be
146 used to refer to the last line. If no lines are specified, the
147 entire file is listed. If the name of a procedure or function
148 is given lines n-k to n+k are listed where n is the first state‐
149 ment in the procedure or function and k is small.
150 file [filename]
152 Change the current source file name to filename. If none is
153 specified then the current source file name is printed.
154 edit [filename]
156 edit procedure/function-name
157 Invoke an editor on filename or the current source file if none
158 is specified. If a procedure or function name is specified, the
159 editor is invoked on the file that contains it. Which editor is
160 invoked by default depends on the installation. The default can
161 be overridden by setting the environment variable EDITOR to the
162 name of the desired editor.
163 pi Recompile the program and read in the new symbol table informa‐
165 tion.
166 sh command-line
168 Pass the command line to the shell for execution. The SHELL
169 environment variable determines which shell is used.
170 alias new-command-name old-command-name
172 This command makes pdx respond to new-command-name the way it
173 used to respond to old-command-name.
174 quit Exit pdx.
176 The following commands deal with the program at the px instruction
182 level rather than source level. They are not intended for general use.
183 tracei [address] [if cond]
185 tracei [variable] [at address] [if cond]
186 stopi [address] [if cond]
187 stopi [at] [address] [if cond]
188 Turn on tracing or set a stop using a px machine instruction
189 addresses.
190 xi address [, address]
192 Print the instructions starting at the first address. Instruc‐
193 tions up to the second address are printed.
194 xd address [, address]
196 Print in octal the specified data location(s).
197
199 obj Pascal object file
200 .pdxinit Pdx initialization file
201
204 pi(1), px(1)
205 An Introduction to Pdx
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208 Pdx does not understand sets, and provides no information about files.
209 The whatis command doesn't quite work for variant records.
211 Bad things will happen if a procedure invoked with the call command
213 does a non-local goto.
214 The commands step and next should be able to take a count that speci‐
216 fies how many lines to execute.
217 There should be commands stepi and nexti that correspond to step and
219 next but work at the instruction level.
220 There should be a way to get an address associated with a line number,
222 procedure or function, and variable.
223 Most of the command names are too long.
225 The alias facility is quite weak.
227 A csh-like history capability would improve the situation.
2294.2 Berkeley Distribution April 29, 1985 PDX(1)