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Some commands accept options starting with a leading dash. For
example, print -pretty
. Similarly to command names, you can
abbreviate a GDB option to the first few letters of the
option name, if that abbreviation is unambiguous, and you can also use
the TAB key to get GDB to fill out the rest of a word
in an option (or to show you the alternatives available, if there is
more than one possibility).
Some commands take raw input as argument. For example, the print
command processes arbitrary expressions in any of the languages
supported by GDB. With such commands, because raw input may
start with a leading dash that would be confused with an option or any
of its abbreviations, e.g. print -p
(short for print
-pretty
or printing negative p
?), if you specify any command
option, then you must use a double-dash (--
) delimiter to
indicate the end of options.
Some options are described as accepting an argument which can be
either on
or off
. These are known as boolean
options. Similarly to boolean settings commands—on
and
off
are the typical values, but any of 1
, yes
and
enable
can also be used as “true” value, and any of 0
,
no
and disable
can also be used as “false” value. You
can also omit a “true” value, as it is implied by default.
For example, these are equivalent:
(gdb) print -object on -pretty off -element unlimited -- *myptr (gdb) p -o -p 0 -e u -- *myptr
You can discover the set of options some command accepts by completing
on -
after the command name. For example:
(gdb) print -TABTAB -address -max-depth -object -static-members -array -memory-tag-violations -pretty -symbol -array-indexes -nibbles -raw-values -union -elements -null-stop -repeats -vtbl
Completion will in some cases guide you with a suggestion of what kind of argument an option expects. For example:
(gdb) print -elements TABTAB NUMBER unlimited
Here, the option expects a number (e.g., 100
), not literal
NUMBER
. Such metasyntactical arguments are always presented in
uppercase.
(For more on using the print
command, see Examining
Data.)
Next: Help, Previous: Filename Arguments, Up: Commands [Contents][Index]