"When I was first introduced to programming (back with
DOS), I used to add mouse support to my applications to impress my
teachers. Programming the mouse largely consisted of putting the
right values in the registers (like 0x00 in the ax register to
reset the mouse) and calling the interrupt service routine with
int86 ( a function provided by Turbo C to access interrupt service
routines). So when I put my hands on a Linux box, I looked for some
thing similar. I soon found out that only root can access hardware
registers directly. But there's an elegant way to handle this.
Welcome to the world of gpm and its client libraries. When I
started searching for useful information about how to program
mouses in UNIX (Linux in particular), I found some C code that let
people access and program the mouse through /dev/mouse . But I was
overwhelmed by the intricacies of handling different mice and was
forced to look for other avenues. After pouring over the man pages
of gpm, I learned to program the mouse with ease, and in no time, I
was playing withmy mouse. I was quite impressed by the extent of
services these libraries provided and was compelled to explore them
further.
It is quite easy to program with gpm and write portable and
robust applications with a few lines of code. In this article, I
will explain the concepts involved in programming the mouse with
simple but effective examples. To compile them you will need
libgpm, which can be obtained from ftp.prosa.it/pub/gpm. To compile
the program successfully, you will have to add the -lgpm flag:"
