Debugging with GDB (September 2007)

Chapter 21: The gd b/mi Interface 277
^done,BreakpointTable={nr_rows="2",nr_cols="6",
hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"},
{width="14",alignment="-1",col_name="type",colhdr="Type"},
{width="4",alignment="-1",col_name="disp",colhdr="Disp"},
{width="3",alignment="-1",col_name="enabled",colhdr="Enb"},
{width="10",alignment="-1",col_name="addr",colhdr="Address"},
{width="40",alignment="2",col_name="what",colhdr="What"}],
body=[bkpt={number="1",type="breakpoint",disp="keep",enabled="y",
addr="0x000100d0",func="main",file="hello.c",line="5",times="0"},
bkpt={number="2",type="breakpoint",disp="keep",enabled="y",
addr="0x00010114",func="foo",file="hello.c",line="13",times="0"}]}
(gdb)
Here’s an example of the result when there are no breakpoints:
(gdb)
-break-list
^done,BreakpointTable={nr_rows="0",nr_cols="6",
hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"},
{width="14",alignment="-1",col_name="type",colhdr="Type"},
{width="4",alignment="-1",col_name="disp",colhdr="Disp"},
{width="3",alignment="-1",col_name="enabled",colhdr="Enb"},
{width="10",alignment="-1",col_name="addr",colhdr="Address"},
{width="40",alignment="2",col_name="what",colhdr="What"}],
body=[]}
(gdb)
The -break-watch comm and
Synopsis
-break-watch [ -a | -r ]
Create a watchpoint. With the ‘-a’ option it will create an access watchpoint, i.e. a
watchpoint that triggers either on a read from or on a write to the memory location. With
the ‘-r’ option, the watchpoint created is a read watchpoint, i.e. it will trigger only when
the memory location is accessed for reading. Without either of the options, the watchpoint
created is a regular watchpoint, i.e. it will trigger when the memory location is accessed
for writing. See hundefinedi [Setting watchpoints], page hundefinedi.
Note that ‘-break-list’ will report a single list of watchpoints and breakpoints inserted.
GDB command
The corresponding GDB commands are ‘watch’, ‘awatch’, and ‘rwatch’.
Example
Setting a watchp oint on a variable in the main function:
(gdb)
-break-watch i
^done,wpt=number="2",exp="i"
(gdb)
-exec-continue