By default, GDB opens the file containing your program's executable code (or the corefile) read-only. This prevents accidental alterations to machine code; but it also prevents you from intentionally patching your program's binary.
If you'd like to be able to patch the binary, you can specify that
explicitly with the set write
command. For example, you might
want to turn on internal debugging flags, or even to make emergency
repairs.
set write on
set write off
exec-file
or core-file
command) after changing set
write
, for your new setting to take effect.
show write
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