duckdb/scripts/lldb/print_array

LLDB Pointer Array Printer

This helper adds a small LLDB command for printing a fixed-size array that lives behind a pointer expression.

Usage

Import the script:

command script import <duckdb repository root>/scripts/lldb/print_array/print_array.py

Then call:

print_array <path> <size>

Examples:

print_array result_sel.sel_vector 1024
print_array row_ids count
print_array data_ptr standard_vector_size

Arguments

• <path> must evaluate to a non-null pointer in the selected frame
• <size> must evaluate to a positive integer
• fractional sizes are rejected, and size expressions are evaluated once

<size> can be either:

• a decimal literal such as 1024
• an expression LLDB can evaluate in the selected frame, such as count

Quote arguments containing spaces, for example:

print_array "row_ids + offset" "count - offset"

The command cannot determine the allocation's bounds; keep the size within the known valid element count.

Behavior

The command:

• validates that a target, process, thread, and frame are selected
• evaluates the pointer expression
• checks that the result is a non-null pointer
• derives the pointee type
• prints the pointee as (<type>[<size>])

Internally it issues an LLDB expression equivalent to:

*((<pointee type> (*)[<size>])(<path>))

Help

You can ask LLDB for the built-in usage text with:

print_array --help