Category: <b>no classification</b>
<br>Flags: Undocumented function<p>
<pre><b>INT 21 - Headroom - API</b>

	AX = 5758h
	BL = function
	    00h ???
	    01h get Headroom location
		Return: CF clear if installed
			    AX = PSP segment of Headroom TSR
			    BX = paragraphs of memory used by Headroom
			CF set if not (normal DOS return)
		Note:	this function is also used as an installation check
	    02h get INT 21 handler
		Return: CF clear
			ES:BX -&gt; Headroom's INT 21 handler
		Note: also sets unknown flag
	    03h launch application???
		DS:SI -&gt; 233-byte application record
		Return: ???
	    04h ???
		???
		Return: CF clear
	    05h get swap directory
		Return: CF clear
			DX:AX -&gt; ASCIZ swap directory name
	    06h ???
		DX = ???
		Return: CF clear
	    07h ???
	    08h ???
	    09h get current application
		Return: BX = application number
	    0Ah ???
		DX = application number
		DS:SI = ???
		Return: ???
	    0Bh ???
	    0Ch ???
		DX = application number
		???
		Return: ???
	    0Dh ???
		DX = application number
		???
		Return: ???
	    0Eh get ???
		Return: CF clear
			AX = ???
	    0Fh set ??? flag
	    10h clear ??? flag
	    11h find application by name
		DS:SI -&gt; ASCIZ application name
		Return: CF clear
			AX = application number or FFFFh if not loaded
	    12h ???
		DX = application number
		Return: CF clear
			???
	    13h ???
		Return: CF clear
	    14h ???
		same as function 13h
	    15h set ???
		DX = ???
	    16h get ???
		Return: AX = ??? set by function 15h
	    17h get ???
		Return: BX = ???
			CX = ??? (may be pointer in BX:CX)
	    18h BUG: branches incorrectly due to fencepost error
Program: Headroom is a TSR/task switcher by Helix Software
SeeAlso: AX=4C57h,AX=5757h,INT 2F/AX=5758h
</pre>