Debugging with GDB: List

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### 9.1 Printing Source Lines

To print lines from a source file, use the `list` command (abbreviated `l`). By default, ten lines are printed. There are several ways to specify what part of the file you want to print; see Location Specifications, for the full list.

Here are the forms of the `list` command most commonly used:

`list linenum`

  Print lines centered around line number linenum in the current source file.

`list function`

  Print lines centered around the beginning of function function.

`list`

  Print more lines. If the last lines printed were printed with a `list` command, this prints lines following the last lines printed; however, if the last line printed was a solitary line printed as part of displaying a stack frame (see Examining the Stack), this prints lines centered around that line.

`list -`

  Print lines just before the lines last printed.

By default, GDB prints ten source lines with any of these forms of the `list` command. You can change this using `set listsize`:

`set listsize count`
`set listsize unlimited`

  Make the `list` command display count source lines (unless the `list` argument explicitly specifies some other number). Setting count to `unlimited` or 0 means there’s no limit.

`show listsize`

  Display the number of lines that `list` prints.

Repeating a `list` command with `RET` discards the argument, so it is equivalent to typing just `list`. This is more useful than listing the same lines again. An exception is made for an argument of ‘`-`’; that argument is preserved in repetition so that each repetition moves up in the source file.

In general, the `list` command expects you to supply zero, one or two location specs. These location specs are interpreted to resolve to source code lines; there are several ways of writing them (see Location Specifications), but the effect is always to resolve to some source lines to display.

Here is a complete description of the possible arguments for `list`:

`list locspec`

  Print lines centered around the line or lines of all the code locations that result from resolving locspec.

`list first,last`

  Print lines from first to last. Both arguments are location specs. When a `list` command has two location specs, and the source file of the second location spec is omitted, this refers to the same source file as the first location spec. If either first or last resolve to more than one source line in the program, then the list command shows the list of resolved source lines and does not proceed with the source code listing.

`list ,last`

  Print lines ending with last.

  Likewise, if last resolves to more than one source line in the program, then the list command prints the list of resolved source lines and does not proceed with the source code listing.

`list first,`

  Print lines starting with first.

`list +`

  Print lines just after the lines last printed.

`list -`

  Print lines just before the lines last printed.

`list`

  As described in the preceding table.

Next: Location Specifications, Up: Source [Contents][Index]