8.5 Applying a Command to Several Frames.

frame apply [all | count | -count | level level...] [flag]... command

The frame apply command allows you to apply the named command to one or more frames.

all

Specify all to apply command to all frames.

count

Use count to apply command to the innermost count frames, where count is a positive number.

-count

Use -count to apply command to the outermost count frames, where count is a positive number.

level

Use level to apply command to the set of frames identified by the level list. level is a frame level or a range of frame levels as level1-level2. The frame level is the number shown in the first field of the ‘backtrace’ command output. E.g., ‘2-4 6-8 3’ indicates to apply command for the frames at levels 2, 3, 4, 6, 7, 8, and then again on frame at level 3.

Note that the frames on which frame apply applies a command are also influenced by the set backtrace settings such as set backtrace past-main and set backtrace limit N. See See Backtraces.

The flag arguments control what output to produce and how to handle errors raised when applying command to a frame. flag must start with a - directly followed by one letter in qcs. If several flags are provided, they must be given individually, such as -c -q.

By default, gdb displays some frame information before the output produced by command, and an error raised during the execution of a command will abort frame apply. The following flags can be used to fine-tune this behavior:

-c

The flag -c, which stands for ‘continue’, causes any errors in command to be displayed, and the execution of frame apply then continues.

-s

The flag -s, which stands for ‘silent’, causes any errors or empty output produced by a command to be silently ignored. That is, the execution continues, but the frame information and errors are not printed.

-q

The flag -q (‘quiet’) disables printing the frame information.

The following example shows how the flags -c and -s are working when applying the command p j to all frames, where variable j can only be successfully printed in the outermost #1 main frame.

     (gdb) frame apply all p j
     #0  some_function (i=5) at fun.c:4
     No symbol "j" in current context.
     (gdb) frame apply all -c p j
     #0  some_function (i=5) at fun.c:4
     No symbol "j" in current context.
     #1  0x565555fb in main (argc=1, argv=0xffffd2c4) at fun.c:11
     $1 = 5
     (gdb) frame apply all -s p j
     #1  0x565555fb in main (argc=1, argv=0xffffd2c4) at fun.c:11
     $2 = 5
     (gdb)

By default, ‘frame apply’, prints the frame location information before the command output:

     (gdb) frame apply all p $sp
     #0  some_function (i=5) at fun.c:4
     $4 = (void *) 0xffffd1e0
     #1  0x565555fb in main (argc=1, argv=0xffffd2c4) at fun.c:11
     $5 = (void *) 0xffffd1f0
     (gdb)

If flag -q is given, no frame information is printed:

     (gdb) frame apply all -q p $sp
     $12 = (void *) 0xffffd1e0
     $13 = (void *) 0xffffd1f0
     (gdb)

faas command

Shortcut for frame apply all -s command. Applies command on all frames, ignoring errors and empty output.

It can for example be used to print a local variable or a function argument without knowing the frame where this variable or argument is, using:

          (gdb) faas p some_local_var_i_do_not_remember_where_it_is

Note that the command tfaas command applies command on all frames of all threads. See See Threads.