Function 03h Auxiliary Input

mov ah, 03h ;Auxiliary Input

int 21h

mov InputChar, al ;character from auxiliary input

Auxiliary Input (Function 03h) reads a character from the standard auxiliary device. If no character is available, MS-DOS waits.

This function has been superseded by Read File or Device (Function 3Fh).

Parameters

This function has no parameters.

Return Value

The AL register contains the ASCII value of the input character.

Comment

As this function receives characters from the standard auxiliary device, it does not save them in a buffer. Therefore, if the device is sending data faster than the program can process it, characters may be lost.

See Also

Function 04h Auxiliary Output
Function 3Fh Read File or Device