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dd3b648e RP |
1 | GDB 4.0 -- what has changed since 3.5? |
2 | ||
3 | * New Facilities | |
4 | ||
a1002e9a JK |
5 | Wide output is wrapped at good places to make the output more |
6 | readable. | |
dd3b648e RP |
7 | |
8 | Gdb now supports cross-debugging from a host machine of one type to a | |
9 | target machine of another type. Communication with the target system | |
10 | is over serial lines. The ``target'' command handles connecting to the | |
11 | remote system; the ``load'' command will download a program into the | |
12 | remote system. It also supports debugging of realtime processes | |
13 | running under VxWorks, using SunRPC Remote Procedure Calls over TCP/IP | |
14 | to talk to a debugger stub on the target system. | |
15 | ||
16 | New CPUs supported include the AMD 29000 and Intel 960. | |
17 | ||
18 | GDB now reads object files and symbol tables via a ``binary file'' | |
19 | library, which allows a single copy of GDB to debug programs of multiple | |
20 | object file types such as a.out and coff. | |
21 | ||
22 | There is now a GDB reference card in "gdbrc.tex". | |
23 | ||
24 | ||
25 | * Control-Variable user interface simplified | |
26 | ||
27 | All variables that control the operation of the debugger can be set | |
28 | by the ``set'' command, and displayed by the ``show'' command. | |
29 | ||
30 | For example, ``set prompt new-gdb=>'' will change your prompt to new-gdb=>. | |
31 | ``Show prompt'' produces the response: | |
32 | Gdb's prompt is new-gdb=>. | |
33 | ||
34 | What follows are the NEW set commands. The command ``help set'' will | |
35 | print a complete list of old and new set commands. ``help set FOO'' | |
adf2bb58 JG |
36 | will give a longer description of the variable FOO. ``show'' will show |
37 | all of the variable descriptions and their current settings. | |
dd3b648e | 38 | |
a1002e9a | 39 | confirm on/off: Enables warning questions for operations that are |
dd3b648e RP |
40 | hard to recover from, e.g. rerunning the program while |
41 | it is already running. Default is ON. | |
42 | ||
43 | editing on/off: Enables EMACS style command line editing | |
44 | of input. Previous lines can be recalled with | |
45 | control-P, the current line can be edited with control-B, | |
46 | you can search for commands with control-R, etc. | |
47 | Default is ON. | |
48 | ||
49 | history filename NAME: NAME is where the gdb command history | |
50 | will be stored. The default is .gdb_history, | |
51 | or the value of the environment variable | |
52 | GDBHISTFILE. | |
53 | ||
54 | history size N: The size, in commands, of the command history. The | |
55 | default is 256, or the value of the environment variable | |
56 | HISTSIZE. | |
57 | ||
58 | history write on/off: If this value is set to ON, the history file will | |
59 | be saved after exiting gdb. If set to OFF, the | |
60 | file will not be saved. The default is OFF. | |
61 | ||
62 | history expansion on/off: If this value is set to ON, then csh-like | |
63 | history expansion will be performed on | |
64 | command line input. The default is OFF. | |
65 | ||
66 | radix N: Sets the default radix for input and output. It can be set | |
67 | to 8, 10, or 16. Note that the argument to "radix" is interpreted | |
68 | in the current radix, so "set radix 10" is always a no-op. | |
69 | ||
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70 | height N: This integer value is the number of lines on a page. Default |
71 | is 24, the current `stty rows'' setting, or the ``li#'' | |
72 | setting from the termcap entry matching the environment | |
73 | variable TERM. | |
dd3b648e | 74 | |
adf2bb58 JG |
75 | width N: This integer value is the number of characters on a line. |
76 | Default is 80, the current `stty cols'' setting, or the ``co#'' | |
77 | setting from the termcap entry matching the environment | |
78 | variable TERM. | |
dd3b648e | 79 | |
a1002e9a JK |
80 | Note: ``set screensize'' is obsolete. Use ``set height'' and |
81 | ``set width'' instead. | |
dd3b648e | 82 | |
a1002e9a | 83 | print address on/off: Print memory addresses in various command displays, |
dd3b648e RP |
84 | such as stack traces and structure values. Gdb looks |
85 | more ``symbolic'' if you turn this off; it looks more | |
86 | ``machine level'' with it on. Default is ON. | |
87 | ||
a1002e9a | 88 | print array on/off: Prettyprint arrays. New convenient format! Default |
dd3b648e RP |
89 | is OFF. |
90 | ||
a1002e9a JK |
91 | print demangle on/off: Print C++ symbols in "source" form if on, |
92 | "raw" form if off. | |
dd3b648e | 93 | |
a1002e9a JK |
94 | print asm-demangle on/off: Same, for assembler level printouts |
95 | like instructions. | |
dd3b648e | 96 | |
a1002e9a | 97 | print vtbl on/off: Prettyprint C++ virtual function tables. Default is OFF. |
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98 | |
99 | ||
100 | * Support for Epoch Environment. | |
101 | ||
102 | The epoch environment is a version of Emacs v18 with windowing. One | |
103 | new command, ``inspect'', is identical to ``print'', except that if you | |
104 | are running in the epoch environment, the value is printed in its own | |
105 | window. | |
106 | ||
107 | ||
108 | * Support for Shared Libraries | |
109 | ||
110 | GDB can now debug programs and core files that use SunOS shared libraries. | |
111 | Symbols from a shared library cannot be referenced | |
112 | before the shared library has been linked with the program (this | |
113 | happens after you type ``run'' and before the function main() is entered). | |
114 | At any time after this linking (including when examining core files | |
115 | from dynamically linked programs), gdb reads the symbols from each | |
116 | shared library when you type the ``sharedlibrary'' command. | |
117 | It can be abbreviated ``share''. | |
118 | ||
119 | sharedlibrary REGEXP: Load shared object library symbols for files | |
120 | matching a unix regular expression. No argument | |
121 | indicates to load symbols for all shared libraries. | |
122 | ||
123 | info sharedlibrary: Status of loaded shared libraries. | |
124 | ||
125 | ||
126 | * Watchpoints | |
127 | ||
128 | A watchpoint stops execution of a program whenever the value of an | |
129 | expression changes. Checking for this slows down execution | |
130 | tremendously whenever you are in the scope of the expression, but is | |
131 | quite useful for catching tough ``bit-spreader'' or pointer misuse | |
132 | problems. Some machines such as the 386 have hardware for doing this | |
133 | more quickly, and future versions of gdb will use this hardware. | |
134 | ||
135 | watch EXP: Set a watchpoint (breakpoint) for an expression. | |
136 | ||
137 | info watchpoints: Information about your watchpoints. | |
138 | ||
139 | delete N: Deletes watchpoint number N (same as breakpoints). | |
140 | disable N: Temporarily turns off watchpoint number N (same as breakpoints). | |
141 | enable N: Re-enables watchpoint number N (same as breakpoints). | |
142 | ||
143 | ||
144 | * C++ multiple inheritance | |
145 | ||
146 | When used with a GCC version 2 compiler, GDB supports multiple inheritance | |
147 | for C++ programs. | |
148 | ||
149 | * C++ exception handling | |
150 | ||
151 | Gdb now supports limited C++ exception handling. Besides the existing | |
152 | ability to breakpoint on an exception handler, gdb can breakpoint on | |
153 | the raising of an exception (before the stack is peeled back to the | |
154 | handler's context). | |
155 | ||
156 | catch FOO: If there is a FOO exception handler in the dynamic scope, | |
157 | set a breakpoint to catch exceptions which may be raised there. | |
158 | Multiple exceptions (``catch foo bar baz'') may be caught. | |
159 | ||
160 | info catch: Lists all exceptions which may be caught in the | |
161 | current stack frame. | |
162 | ||
163 | ||
164 | * Minor command changes | |
165 | ||
166 | The command ``call func (arg, arg, ...)'' now acts like the print | |
167 | command, except it does not print or save a value if the function's result | |
168 | is void. This is similar to dbx usage. | |
169 | ||
170 | The ``up'' and ``down'' commands now always print the frame they end up | |
171 | at; ``up-silently'' and `down-silently'' can be used in scripts to change | |
172 | frames without printing. | |
173 | ||
174 | * New directory command | |
175 | ||
176 | 'dir' now adds directories to the FRONT of the source search path. | |
177 | The path starts off empty. Source files that contain debug information | |
178 | about the directory in which they were compiled can be found even | |
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179 | with an empty path; Sun CC and GCC include this information. If GDB can't |
180 | find your source file in the current directory, type "dir .". | |
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181 | |
182 | * Configuring GDB for compilation | |
183 | ||
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184 | For normal use, type ``./configure host''. See README or gdb.texinfo |
185 | for more details. | |
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186 | |
187 | GDB now handles cross debugging. If you are remotely debugging between | |
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188 | two different machines, type ``./configure host -target=targ''. |
189 | Host is the machine where gdb will run; targ is the machine | |
dd3b648e | 190 | where the program that you are debugging will run. |