[mt2002]

Hey everyone,

What exactally happens when you let the compiler assign a string buffer to a pointer? ie: char* p = "Hello, world!"; but assigning the string from a superclass to a subclass pointer? Are they both handled the same?

I have the following code:

class cmd_title : public internal_cmd {

public:

	cmd_title () {

		m_flags=BUILTIN_CMDLINE|BUILTIN_HELP_LIST;
		m_name="title";
		m_doc="title [NAME]\n\r\Add a new boot entry";		//invalid instruction??
	}

	virtual	int callback (char* cmd, int parms) {

		core* p = core::get();

		if (p)
			p->get_bios()->puts ("\n\r%s", m_doc);

		return 0;
	};
};

m_doc is simply a char* declared in the base class internal_cmd. The above code seems to either page fault or cause an invalid instruction when m_doc is displayed (The call to puts() ).

An interesting thing to note is, if I shorten the m_doc string by so much it gets displayed fine and works. What is more interesting is that it will only cause a problem if I display it which has me somewhat lost.

Does anyone know what can cause this to happen? I can probably get this working if I declare m_doc as a static array, but I am curious about this one

Please keep in mind this is running in ring 0 (supervisor mode).

This makes me worried so I decided to post here to see what others ideas are. Thanks for any input

[mt2002]

I decided to not store the description string (the m_doc pointer) and just do it manually via p->get_bios()->puts ("string"); and it worked fine.

Im still unsure of why I could not store or work with any static string passed to puts() (That is, the following crashed the same way) :

static char* t = "test long string";
p->get_bios()->puts ("%s", t);

But it works fine in any other part of the code and if I do the above manually rather then storing it. Weird.

Im going to mark this solved sense I found a solution but I still am open for possible suggestions for what can cause something like this to happen...