On 23/07/19 11:42, Stefano Garzarella wrote:
> "If writable is TRUE, the mapped buffer may be modified, otherwise it is an
> error to modify the mapped buffer. Modifications to the buffer are not visible
> to other processes mapping the same file, and are not written back to the
> file."
>
> I don't know what "error" means, but reading the second part I thought
> the changes in that case were only visible at the current process.
My reading would be that the second part applies to the writable==TRUE
case. In fact, the glib source code agrees:
file->contents = (gchar *) mmap (NULL, file->length,
writable ? PROT_READ|PROT_WRITE : PROT_READ,
MAP_PRIVATE, fd, 0);
meaning that we could after all just use writable == true.
Paolo
> I'll test it to understand better the behavior. If we can't touch it, then we
> have to make a copy in these cases.
>
>> (We can't get out of this by just passing writable=true, because
>> we definitely don't want to be writing back to the underlying file.)
> Yes, I agree.
