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dd3b648e RP |
1 | GDB 4.0 -- what has changed since 3.5? |
2 | ||
3 | * New Facilities | |
4 | ||
5 | Gdb now paginates its output, with a ``more''-like interface. You can | |
6 | set the screen width and screen height with new ``set'' commands; they | |
7 | default to your terminal settings. Wide output is wrapped at good | |
8 | places to make the output more readable. | |
9 | ||
10 | Gdb now reads its input via the ``readline'' interface. This provides | |
11 | inline editing of commands, using familiar Emacs or VI commands (like | |
12 | ``tcsh'' or the korn shell); history substitutions a la the C shell; | |
13 | and storage and recall of your command history across debugging | |
14 | sessions. The default is Emacs mode; to switch temporarily to vi mode, | |
15 | use control-meta-J or ESC control-j. You can switch permanently to vi | |
16 | mode by putting the line ``set editing-mode vi'' in the file .inputrc | |
17 | in your home directory. For full details, see the description in | |
18 | readline/inc-readline.texinfo and readline/inc-history.texinfo. | |
19 | ||
20 | Gdb now supports cross-debugging from a host machine of one type to a | |
21 | target machine of another type. Communication with the target system | |
22 | is over serial lines. The ``target'' command handles connecting to the | |
23 | remote system; the ``load'' command will download a program into the | |
24 | remote system. It also supports debugging of realtime processes | |
25 | running under VxWorks, using SunRPC Remote Procedure Calls over TCP/IP | |
26 | to talk to a debugger stub on the target system. | |
27 | ||
28 | New CPUs supported include the AMD 29000 and Intel 960. | |
29 | ||
30 | GDB now reads object files and symbol tables via a ``binary file'' | |
31 | library, which allows a single copy of GDB to debug programs of multiple | |
32 | object file types such as a.out and coff. | |
33 | ||
34 | There is now a GDB reference card in "gdbrc.tex". | |
35 | ||
36 | ||
37 | * Control-Variable user interface simplified | |
38 | ||
39 | All variables that control the operation of the debugger can be set | |
40 | by the ``set'' command, and displayed by the ``show'' command. | |
41 | ||
42 | For example, ``set prompt new-gdb=>'' will change your prompt to new-gdb=>. | |
43 | ``Show prompt'' produces the response: | |
44 | Gdb's prompt is new-gdb=>. | |
45 | ||
46 | What follows are the NEW set commands. The command ``help set'' will | |
47 | print a complete list of old and new set commands. ``help set FOO'' | |
48 | will give a longer description of the variable FOO. | |
49 | ||
50 | caution on/off: Enables warning questions for operations that are | |
51 | hard to recover from, e.g. rerunning the program while | |
52 | it is already running. Default is ON. | |
53 | ||
54 | editing on/off: Enables EMACS style command line editing | |
55 | of input. Previous lines can be recalled with | |
56 | control-P, the current line can be edited with control-B, | |
57 | you can search for commands with control-R, etc. | |
58 | Default is ON. | |
59 | ||
60 | history filename NAME: NAME is where the gdb command history | |
61 | will be stored. The default is .gdb_history, | |
62 | or the value of the environment variable | |
63 | GDBHISTFILE. | |
64 | ||
65 | history size N: The size, in commands, of the command history. The | |
66 | default is 256, or the value of the environment variable | |
67 | HISTSIZE. | |
68 | ||
69 | history write on/off: If this value is set to ON, the history file will | |
70 | be saved after exiting gdb. If set to OFF, the | |
71 | file will not be saved. The default is OFF. | |
72 | ||
73 | history expansion on/off: If this value is set to ON, then csh-like | |
74 | history expansion will be performed on | |
75 | command line input. The default is OFF. | |
76 | ||
77 | radix N: Sets the default radix for input and output. It can be set | |
78 | to 8, 10, or 16. Note that the argument to "radix" is interpreted | |
79 | in the current radix, so "set radix 10" is always a no-op. | |
80 | ||
81 | screen-height N: This integer value is the number of lines on a page. Default | |
82 | is 24, the current `stty rows'' setting, or the ``li#'' | |
83 | setting from the termcap entry matching the environment | |
84 | variable TERM. | |
85 | ||
86 | screen-width N: This integer value is the number of characters on a line. | |
87 | Default is 80, the current `stty cols'' setting, or the ``co#'' | |
88 | setting from the termcap entry matching the environment | |
89 | variable TERM. | |
90 | ||
91 | Note: ``set screensize'' is obsolete. Use ``set screen-height'' and | |
92 | ``set screen-width'' instead. | |
93 | ||
94 | addressprint on/off: Print memory addresses in various command displays, | |
95 | such as stack traces and structure values. Gdb looks | |
96 | more ``symbolic'' if you turn this off; it looks more | |
97 | ``machine level'' with it on. Default is ON. | |
98 | ||
99 | arrayprint on/off: Prettyprint arrays. New convenient format! Default | |
100 | is OFF. | |
101 | ||
102 | demangle on/off: Print C++ symbols in "source" form if on, "raw" form if off. | |
103 | ||
104 | asm-demangle on/off: Same, for assembler level printouts like instructions. | |
105 | ||
106 | vtblprint on/off: Prettyprint C++ virtual function tables. Default is OFF. | |
107 | ||
108 | ||
109 | * Support for Epoch Environment. | |
110 | ||
111 | The epoch environment is a version of Emacs v18 with windowing. One | |
112 | new command, ``inspect'', is identical to ``print'', except that if you | |
113 | are running in the epoch environment, the value is printed in its own | |
114 | window. | |
115 | ||
116 | ||
117 | * Support for Shared Libraries | |
118 | ||
119 | GDB can now debug programs and core files that use SunOS shared libraries. | |
120 | Symbols from a shared library cannot be referenced | |
121 | before the shared library has been linked with the program (this | |
122 | happens after you type ``run'' and before the function main() is entered). | |
123 | At any time after this linking (including when examining core files | |
124 | from dynamically linked programs), gdb reads the symbols from each | |
125 | shared library when you type the ``sharedlibrary'' command. | |
126 | It can be abbreviated ``share''. | |
127 | ||
128 | sharedlibrary REGEXP: Load shared object library symbols for files | |
129 | matching a unix regular expression. No argument | |
130 | indicates to load symbols for all shared libraries. | |
131 | ||
132 | info sharedlibrary: Status of loaded shared libraries. | |
133 | ||
134 | ||
135 | * Watchpoints | |
136 | ||
137 | A watchpoint stops execution of a program whenever the value of an | |
138 | expression changes. Checking for this slows down execution | |
139 | tremendously whenever you are in the scope of the expression, but is | |
140 | quite useful for catching tough ``bit-spreader'' or pointer misuse | |
141 | problems. Some machines such as the 386 have hardware for doing this | |
142 | more quickly, and future versions of gdb will use this hardware. | |
143 | ||
144 | watch EXP: Set a watchpoint (breakpoint) for an expression. | |
145 | ||
146 | info watchpoints: Information about your watchpoints. | |
147 | ||
148 | delete N: Deletes watchpoint number N (same as breakpoints). | |
149 | disable N: Temporarily turns off watchpoint number N (same as breakpoints). | |
150 | enable N: Re-enables watchpoint number N (same as breakpoints). | |
151 | ||
152 | ||
153 | * C++ multiple inheritance | |
154 | ||
155 | When used with a GCC version 2 compiler, GDB supports multiple inheritance | |
156 | for C++ programs. | |
157 | ||
158 | * C++ exception handling | |
159 | ||
160 | Gdb now supports limited C++ exception handling. Besides the existing | |
161 | ability to breakpoint on an exception handler, gdb can breakpoint on | |
162 | the raising of an exception (before the stack is peeled back to the | |
163 | handler's context). | |
164 | ||
165 | catch FOO: If there is a FOO exception handler in the dynamic scope, | |
166 | set a breakpoint to catch exceptions which may be raised there. | |
167 | Multiple exceptions (``catch foo bar baz'') may be caught. | |
168 | ||
169 | info catch: Lists all exceptions which may be caught in the | |
170 | current stack frame. | |
171 | ||
172 | ||
173 | * Minor command changes | |
174 | ||
175 | The command ``call func (arg, arg, ...)'' now acts like the print | |
176 | command, except it does not print or save a value if the function's result | |
177 | is void. This is similar to dbx usage. | |
178 | ||
179 | The ``up'' and ``down'' commands now always print the frame they end up | |
180 | at; ``up-silently'' and `down-silently'' can be used in scripts to change | |
181 | frames without printing. | |
182 | ||
183 | * New directory command | |
184 | ||
185 | 'dir' now adds directories to the FRONT of the source search path. | |
186 | The path starts off empty. Source files that contain debug information | |
187 | about the directory in which they were compiled can be found even | |
188 | with an empty path; GCC includes this information. If GDB can't find | |
189 | your source file in the current directory, type "dir .". | |
190 | ||
191 | * Features removed in this release | |
192 | ||
193 | ``info types'' has been removed, since it printed builtin types in a | |
194 | confusing fashion, and did not do useful things with typedefs. ``ptype'' | |
195 | or ``whatis'' are more useful commands for dealing with types.. | |
196 | ||
197 | ||
198 | * Configuring GDB for compilation | |
199 | ||
200 | For normal use, type ``config.gdb host''. Hosts now handled are: | |
201 | ||
202 | 3b1 altos altosgas arm bigmips convex hp300bsd hp300hpux i386v i386v-g | |
203 | i386v32 i386v32-g isi littlemips m88k merlin news news1000 none np1 pn | |
204 | pyramid sun2os3 sun2os4 sun386 sun3os3 sun3os4 sun4os3 sun4os4 symmetry | |
205 | umax vax | |
206 | ||
207 | Type config.gdb +host to get a full description of each host. | |
208 | ||
209 | You can now build gdb conveniently for several architectures from the | |
210 | same sources. If config.gdb is run from a subdirectory, it configures | |
211 | the Makefile to use source files from '..'. Each subdirectory can be | |
212 | indpendently configured. An explicit source file directory can also | |
213 | be specified with the +srcdir=xxx option. Due to obscure search rules | |
214 | in the C preprocessor, if you have previously built gdb in the main | |
215 | directory, run 'make cleanconfig' in the top level directory before | |
216 | building it in a subdirectory. | |
217 | ||
218 | GDB now handles cross debugging. If you are remotely debugging between | |
219 | two different machines, type ``config.gdb host target''. | |
220 | Host is the machine where gdb will run; target is the machine | |
221 | where the program that you are debugging will run. | |
222 | ||
223 | Type config.gdb +target to get a full description of each target. |