gdb/WHATS.NEW

   1                 What has changed since GDB-3.5?
   2                 (Organized release by release)
   3
   4 *** Changes in GDB-4.2:
   5
   6  *  Improved configuration
   7
   8 Only one copy of `configure' exists now, and it is not self-modifying.
   9 Porting BFD is simpler.
  10
  11  *  Stepping improved
  12
  13 The `step' and `next' commands now only stop at the first instruction
  14 of a source line.  This prevents the multiple stops that used to occur
  15 in switch statements, for-loops, etc.  `Step' continues to stop if a
  16 function that has debugging information is called within the line.
  17
  18  *  Bug fixing
  19
  20 Lots of small bugs fixed.  More remain.
  21
  22  *  New host supported (not target)
  23
  24 Intel 386 PC clone running Mach         i386-none-mach
  25
  26
  27 *** Changes in GDB-4.1:
  28
  29  *  Multiple source language support
  30
  31 GDB now has internal scaffolding to handle several source languages.
  32 It determines the type of each source file from its filename extension,
  33 and will switch expression parsing and number formatting to match the
  34 language of the function in the currently selected stack frame.
  35 You can also specifically set the language to be used, with
  36 `set language c' or `set language modula-2'.
  37
  38  *  GDB and Modula-2
  39
  40 GDB now has preliminary support for the GNU Modula-2 compiler,
  41 currently under development at the State University of New York at
  42 Buffalo.  Development of both GDB and the GNU Modula-2 compiler will
  43 continue through the fall of 1991 and into 1992.
  44
  45 Other Modula-2 compilers are currently not supported, and attempting to
  46 debug programs compiled with them will likely result in an error as the
  47 symbol table is read.  Feel free to work on it, though!
  48
  49 There are hooks in GDB for strict type checking and range checking,
  50 in the `Modula-2 philosophy', but they do not currently work.
  51
  52  * set write on/off
  53
  54 GDB can now write to executable and core files (e.g. patch
  55 a variable's value).   You must turn this switch on, specify
  56 the file ("exec foo" or "core foo"), *then* modify it, e.g.
  57 by assigning a new value to a variable.  Modifications take
  58 effect immediately.
  59
  60  * Automatic SunOS shared library reading
  61
  62 When you run your program, GDB automatically determines where its
  63 shared libraries (if any) have been loaded, and reads their symbols.
  64 The `share' command is no longer needed.  This also works when
  65 examining core files.
  66
  67  * set listsize
  68
  69 You can specify the number of lines that the `list' command shows.
  70 The default is 10.
  71
  72  * New machines supported (host and target)
  73
  74 SGI Iris (MIPS) running Irix V3:        mips-sgi-irix   or  iris
  75 Sony NEWS (68K) running NEWSOS 3.x:     m68k-sony-sysv  or  news
  76 Ultracomputer (29K) running Sym1:       a29k-nyu-sym1   or  ultra3
  77
  78  * New hosts supported (not targets)
  79
  80 IBM RT/PC:                              romp-ibm-aix    or  rtpc
  81
  82  * New targets supported (not hosts)
  83
  84 AMD 29000 embedded with COFF            a29k-none-coff
  85 AMD 29000 embedded with a.out           a29k-none-aout
  86 Ultracomputer remote kernel debug       a29k-nyu-kern
  87
  88  * New remote interfaces
  89
  90 AMD 29000 Adapt
  91 AMD 29000 Minimon
  92
  93
  94 *** Changes in GDB-4.0:
  95
  96  *  New Facilities
  97
  98 Wide output is wrapped at good places to make the output more readable.
  99
 100 Gdb now supports cross-debugging from a host machine of one type to a
 101 target machine of another type.  Communication with the target system
 102 is over serial lines.  The ``target'' command handles connecting to the
 103 remote system; the ``load'' command will download a program into the
 104 remote system.  Serial stubs for the m68k and i386 are provided.  Gdb
 105 also supports debugging of realtime processes running under VxWorks,
 106 using SunRPC Remote Procedure Calls over TCP/IP to talk to a debugger
 107 stub on the target system.
 108
 109 New CPUs supported include the AMD 29000 and Intel 960.
 110
 111 GDB now reads object files and symbol tables via a ``binary file''
 112 library, which allows a single copy of GDB to debug programs of multiple
 113 object file types such as a.out and coff.
 114
 115 There is now a GDB reference card in "doc/refcard.tex".  (Make targets
 116 refcard.dvi and refcard.ps are available to format it).
 117
 118
 119  *  Control-Variable user interface simplified
 120
 121 All variables that control the operation of the debugger can be set
 122 by the ``set'' command, and displayed by the ``show'' command.
 123
 124 For example, ``set prompt new-gdb=>'' will change your prompt to new-gdb=>.
 125 ``Show prompt'' produces the response:
 126 Gdb's prompt is new-gdb=>.
 127
 128 What follows are the NEW set commands.  The command ``help set'' will
 129 print a complete list of old and new set commands.  ``help set FOO''
 130 will give a longer description of the variable FOO.  ``show'' will show
 131 all of the variable descriptions and their current settings.
 132
 133 confirm on/off:  Enables warning questions for operations that are
 134                  hard to recover from, e.g. rerunning the program while
 135                  it is already running.  Default is ON.
 136
 137 editing on/off:  Enables EMACS style command line editing
 138                  of input.  Previous lines can be recalled with
 139                  control-P, the current line can be edited with control-B,
 140                  you can search for commands with control-R, etc.
 141                  Default is ON.
 142
 143 history filename NAME:  NAME is where the gdb command history
 144                         will be stored.  The default is .gdb_history,
 145                         or the value of the environment variable
 146                         GDBHISTFILE.
 147
 148 history size N:  The size, in commands, of the command history.  The
 149                  default is 256, or the value of the environment variable
 150                  HISTSIZE.
 151
 152 history save on/off: If this value is set to ON, the history file will
 153                       be saved after exiting gdb.  If set to OFF, the
 154                       file will not be saved.  The default is OFF.
 155
 156 history expansion on/off: If this value is set to ON, then csh-like
 157                           history expansion will be performed  on
 158                           command line input.  The default is OFF.
 159
 160 radix N:  Sets the default radix for input and output.  It can be set
 161           to 8, 10, or 16.  Note that the argument to "radix" is interpreted
 162           in the current radix, so "set radix 10" is always a no-op.
 163
 164 height N: This integer value is the number of lines on a page. Default
 165           is 24, the current `stty rows'' setting, or the ``li#''
 166           setting from the termcap entry matching the environment
 167           variable TERM.
 168
 169 width N:  This integer value is the number of characters on a line.
 170           Default is 80, the current `stty cols'' setting, or the ``co#''
 171           setting from the termcap entry matching the environment
 172           variable TERM.
 173
 174 Note: ``set screensize'' is obsolete. Use ``set height'' and
 175 ``set width'' instead.
 176
 177 print address on/off:  Print memory addresses in various command displays,
 178                       such as stack traces and structure values.  Gdb looks
 179                       more ``symbolic'' if you turn this off; it looks more
 180                       ``machine level'' with it on.  Default is ON.
 181
 182 print array on/off:  Prettyprint arrays.  New convenient format!  Default
 183                     is OFF.
 184
 185 print demangle on/off:   Print C++ symbols in "source" form if on,
 186                         "raw" form if off.
 187
 188 print asm-demangle on/off:  Same, for assembler level printouts
 189                         like instructions.
 190
 191 print vtbl on/off:  Prettyprint C++ virtual function tables.  Default is OFF.
 192
 193
 194  *  Support for Epoch Environment.
 195
 196 The epoch environment is a version of Emacs v18 with windowing.  One
 197 new command, ``inspect'', is identical to ``print'', except that if you
 198 are running in the epoch environment, the value is printed in its own
 199 window.
 200
 201
 202  *  Support for Shared Libraries
 203
 204 GDB can now debug programs and core files that use SunOS shared libraries.
 205 Symbols from a shared library cannot be referenced
 206 before the shared library has been linked with the program (this
 207 happens after you type ``run'' and before the function main() is entered).
 208 At any time after this linking (including when examining core files
 209 from dynamically linked programs), gdb reads the symbols from each
 210 shared library when you type the ``sharedlibrary'' command.
 211 It can be abbreviated ``share''.
 212
 213 sharedlibrary REGEXP:  Load shared object library symbols for files
 214                        matching a unix regular expression.  No argument
 215                        indicates to load symbols for all shared libraries.
 216
 217 info sharedlibrary:  Status of loaded shared libraries.
 218
 219
 220  *  Watchpoints
 221
 222 A watchpoint stops execution of a program whenever the value of an
 223 expression changes.  Checking for this slows down execution
 224 tremendously whenever you are in the scope of the expression, but is
 225 quite useful for catching tough ``bit-spreader'' or pointer misuse
 226 problems.  Some machines such as the 386 have hardware for doing this
 227 more quickly, and future versions of gdb will use this hardware.
 228
 229 watch EXP:  Set a watchpoint (breakpoint) for an expression.
 230
 231 info watchpoints:  Information about your watchpoints.
 232
 233 delete N:   Deletes watchpoint number N (same as breakpoints).
 234 disable N:  Temporarily turns off watchpoint number N (same as breakpoints).
 235 enable N:   Re-enables watchpoint number N (same as breakpoints).
 236
 237
 238  *  C++ multiple inheritance
 239
 240 When used with a GCC version 2 compiler, GDB supports multiple inheritance
 241 for C++ programs.
 242
 243  *  C++ exception handling
 244
 245 Gdb now supports limited C++ exception handling.  Besides the existing
 246 ability to breakpoint on an exception handler, gdb can breakpoint on
 247 the raising of an exception (before the stack is peeled back to the
 248 handler's context).
 249
 250 catch FOO:  If there is a FOO exception handler in the dynamic scope,
 251             set a breakpoint to catch exceptions which may be raised there.
 252             Multiple exceptions (``catch foo bar baz'') may be caught.
 253
 254 info catch:  Lists all exceptions which may be caught in the
 255              current stack frame.
 256
 257
 258  *  Minor command changes
 259
 260 The command ``call func (arg, arg, ...)'' now acts like the print
 261 command, except it does not print or save a value if the function's result
 262 is void.  This is similar to dbx usage.
 263
 264 The ``up'' and ``down'' commands now always print the frame they end up
 265 at; ``up-silently'' and `down-silently'' can be used in scripts to change
 266 frames without printing.
 267
 268  *  New directory command
 269
 270 'dir' now adds directories to the FRONT of the source search path.
 271 The path starts off empty.  Source files that contain debug information
 272 about the directory in which they were compiled can be found even
 273 with an empty path; Sun CC and GCC include this information.  If GDB can't
 274 find your source file in the current directory, type "dir .".
 275
 276  * Configuring GDB for compilation
 277
 278 For normal use, type ``./configure host''.  See README or gdb.texinfo
 279 for more details.
 280
 281 GDB now handles cross debugging.  If you are remotely debugging between
 282 two different machines, type ``./configure host -target=targ''.
 283 Host is the machine where gdb will run; targ is the machine
 284 where the program that you are debugging will run.