Live graph for a C application

Question

I have an application which logs periodically on to a host system it could be on a file or just a console. I would like to use this data to plot a statistical graph for me.

Answer 1

Well, you only need to write your data in the given format of livegraph and set livegraph up to plot what you want. If wrote small C example which generates random numbers and dumps them together with the time every second. Next, you just attach the livegraph program to the file. That's it.

Playing around with LiveGraph I must say that its use is rather limited. I still would stick to a python script with matplotlib, since you have much more control over how and what is plotted.

#include 
#include 
#include 
#include 
#include 

int main(int argc, char** argv)
{
        FILE *f; 
        gsl_rng *r = NULL;
        const gsl_rng_type *T; 
        int seed = 31456;   
        double rndnum;
        T = gsl_rng_ranlxs2;
        r = gsl_rng_alloc(T);
        gsl_rng_set(r, seed);

        time_t t;
        t = time(NULL);



        f = fopen("test.lgdat", "a");
        fprintf(f, "##;##\n");
        fprintf(f,"@LiveGraph test file.\n");
        fprintf(f,"Time;Dataset number\n");

        for(;;){
                rndnum = gsl_ran_gaussian(r, 1); 
                fprintf(f,"%f;%f\n", (double)t, rndnum);
                sleep(1);
                fflush(f);
                t = time(NULL);
        }   

        gsl_rng_free(r);
        return 0;
}

compile with

gcc -Wall main.c  `gsl-config --cflags --libs`