Writing a Mouse-Sensitive Application

 in
Terminal-oriented programs tend to have an unwieldy interface, while writing X-Windows applications is difficult. By using the gpm client library you can easily turn a text-oriented program into an easy-to-port mouse-sensitive application.
Where to Get the Software

The gpm package is available by ftp from sunsite.unc.edu/pub/Linux/system/Daemons/gpm-1.06.tar.gz. Sometimes small improvements don't get to sunsite, because I don't want to fuss up the maintainer. The very latest release is always available from iride.unipv.it/pub/gpm/gpm-1.06.tar.gz.

The source package includes a full info file and a PostScript manual describing the library much more thoroughly. A sample portable application is included as well.

The package is also distributed in binary form (but with the full documentation) with Slackware. If you have had the Slackware distribution through floppy disks, you may want to get the source; otherwise it is in the cdrom. Recently, I've also heard a proposal to “debianize” gpm, so it may appear in the Debian distribution in the near future.

For any question not answered in the documentation, feel free to contact me.

Listing 1. Simple configure.in for a Mouse-Aware Application

dnl configure.in for sample gpm client
dnl This will only run with autoconf-2.0. or later
AC_INIT(rmev.c)
AC_PROG_CC
AC_PROG_CPP
CFLAGS="-O"
LIBS=""
dnl look for libgpm.a; if found assume to have
dnl <gpm.h> as well. Gpm_Repeat is only present
dnl after gpm-0.18
AC_CHECK_LIB(gpm, Gpm_Repeat,[
    GPMXTERM=""
    LIBS="$LIBS -lgpm"],[
    GPMXTERM="gpm-xterm.o"
    if test "-uname-" = Linux
      then AC_MSG_WARN("libgpm.a is missing or old")
    fi
    ])
dnl subsitute @GPMXTERM@ in Makefile
AC_SUBST(GPMXTERM)

Listing 2. Simple Makefile.in for a Mouse-Aware Application

# simple Makefile.in - autoconf will
# replace any @symbol@ with the right value
# include standard stuff
srcdir = @srcdir@
VPATH = @srcdir@
CC = @CC@
CFLAGS = @CFLAGS@
LDFLAGS = @LDFLAGS@
LIBS = @LIBS@
prefix = @prefix@
OBJS = rmev.o @GPMXTERM@
TARGET = rmev
all: configure Makefile $(TARGET)
$(TARGET): $(OBJS)
    $(CC) $(CFLAGS) $(OBJS) $(LDFLAGS) \
               -o $(TARGET) ($LIBS)
clean:
    rm -f *.o $(TARGET) config.*
### rules to automatically rerun autoconf
Makefile: Makefile.in
    ./configure
configure: configure.in
    autoconf
    configure
distrib: clean
    rm -f config.* *~ core
    autoconf
    rm -f Makefile

Alessandro Rubini (rubini@ipvvis.unipv.it) is taking his PhD course in computer science and is breeding two small Linux boxes at home. Wild by his very nature, he loves trekking, canoeing, and riding his bike. He wrote gpm.

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