[Gnuplot-py-users] I found the problem

Thank you all very much. I finally found that the problem was with 
"using" . This is the code with which my program works!

             $fp = popen("gnuplot -","w");
            fputs($fp,"set title \"".$ejey." de los telefonos: 
".$telefonos." desde: ".$limite_inferior." hasta: ".$limite_superior." 
\"\n");
            fputs($fp,"set format y \"%.3f\"\n");
            fputs($fp,"set xlabel \"Fecha\"\n");
            fputs($fp,"set ylabel \"".$ejey."\"\n");
            fputs($fp,"set yrange [:]\n");
            fputs($fp,"set timefmt \"%Y-%m-%d %H:%M:%S\"\n");
            fputs($fp,"set xdata time\n");
            fputs($fp,"set format x \"%Y-%m-%d %H:%M\"\n");
            fputs($fp,"set ytics 0.25\n");
            fputs($fp,"set xtics autofreq\n");
            //fputs($fp, "set xrange [\"".$limite_inferior."\" : 
\"".$limite_superior."\"\n");
            fputs($fp,"set nomx2tics\n");
            fputs($fp,"set nomy2tics\n");
            fputs($fp,"set grid\n");
            fputs($fp,"set size 2\n");
            fputs($fp,"set lmargin 7\n");
            fputs($fp,"set rmargin 2\n");
            fputs($fp,"set tmargin 3\n");
            fputs($fp,"set bmargin 3\n");
            fputs($fp,"set boxwidth 10\n");
            fputs($fp,"set output 
\"/var/www/smtustat/salida_gnuplot.png\"\n");
            fputs($fp,"set terminal png\n");
            fputs($fp,$string_plot."\n");
            for($i=0; $i<$total; $i++)

Do you know if there is any way to call from php to gnuplot, send all 
the points that I send... but not creating a file called 
"salida_gnuplot.png", but simply createn an image on the screen?? I am 
interested in this fact so that more than one user can have access to 
the file at the same time.
Thank you very much again! and I hope this little and simple code can 
help somebody.

See you!!