The following are some examples of software written using gl4c.

mplot.tgz (Redhat 8.0)
How to use mplot:
You need a parameter file called, for example, szk004.idl (you can change the szk to anything you like - it could be the name of your program or the equation you are studying). The numbers following the szk are the 'run number'.
This parameter file contains just one line which must have the following format:
Nx 128 Ny 128 dt 0.005 Sym NO_SYMMETRY Xbc PERIODIC xh 64 xl -64 yh 64 yl -64
Nx,Ny: numbers of points in x and y directions; dt: time step; xh,xl,yh,yl: max,min values of x,y
the name of your data files should be in the form e.g. szk004_0m10000.dat.l (or szk004_0m10000.dat.l.gz if they are gzipped). The '10000' in this example is the iteration number. To display the files szk004_0m0.dat.l, szk004_0m10000.dat.l, szk004_0m20000.dat.l, and szk004_0m30000.dat.l you would need to enter
mplot szk004_0#0:10000:30000
or if, say, you only want to plot 0,10000, and 30000 then
mplot szk004_0#0,10000,30000
The data in the .dat.l files must be stored as floats in binary format (not as text, not as double). In other words, you need to write the data file using the C command fwrite. For example,

ecosystem by Sanida Vichaya.