gdb-cpp-define-alist-program

gdb-cpp-define-alist-program is a variable defined in `gdb-mi.el'.
Its value is

"gcc -E -dM -"

• This variable may be risky if used as a file-local variable.

Documentation:
Shell command for generating a list of defined macros in a source file.
This list is used to display the #define directive associated
with an identifier as a tooltip. It works in a debug session with
GDB, when `gud-tooltip-mode' is t.

Set `gdb-cpp-define-alist-flags' for any include paths or
predefined macros.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 22.1 of Emacs.