mov dx, seg Line
mov ds, dx
mov dx, offset Line ;ds:dx points to buffer to receive input
mov ax, 4810h ;Read Command Line
int 2Fh ;Multiplex Interrupt
Read Command Line (Interrupt 2Fh Function 4810h) reads a line of up to 126 characters and copies it to the specified buffer. While the line is being read, all Doskey function keys and macros are enabled. This means, for example, that the user can select a line from the Doskey history, edit a line, or enter macros that are automatically expanded.
Line
Points to a buffer that receives the command line. The buffer must have the following form:
| Offset | Contents |
| 00h | The maximum size of the buffer. It must be 128 bytes. |
| 01h | A number that is one less than the number of characters read. The function copies a carriage-return character (ASCII 0Dh) to the buffer but does not include the byte in its total. |
| 02h | The first byte of the input line. |
If the function is successful, the AX register contains zero and the input line is copied, along with the number of bytes in the line, to the buffer pointed to by the Line parameter.
If the user types a macro name, AX contains zero, but no text is copied to the buffer. Instead, the program must immediately call the function a second time to expand the macro and copy the macro text to the buffer.
This function adds the command line to the Doskey history. If the user types a macro name or a special parameter (such as $*), the program must call the function a second time to expand the macro or parameter. On the second call, the function automatically writes the expanded macro to the screen, overwriting the macro name. It also copies the expanded macro text to the buffer.