I'm writing a code in c++ which plots a dataset using gnuplot, and I realized that I could simplify my code a lot if I could get variables from gnuplot to my c++ code. e.g. if I did a fit f and get his stats i.e.
f(x)=a*x+b
fit f 'data.txt' via a,b
stats 'data.txt' u (f($1)):2 name 'Sf'
Is there any way to get, for example, the Sf_records and save it to a variable in my code? Like int N = Rf_records?
Thanks for your help
Assuming that you are communicating with gnuplot trougth a FIFO, you can order to gnuplot
print <variable>
and you can read this to your c++ program.
Eg. for reading a varirable:
double getVal(std::string val){
float ret;
std::string str;
str="print "; str+=val;str+="\n";
fprintf(gp, str.c_str());
fflush(gp);
fscanf(gpin, "%f", &ret);
return ret;
}
To open a gnuplot FIFO
void connecttognuplot(){
//make an unique FIFO
std::stringstream alma; alma.str(std::string()); alma<<std::clock(); GPFIFO="./gpio"+alma.str();
//gnuplot => program FIFO
if (mkfifo(GPFIFO.c_str(), 0600)) {
if (errno != EEXIST) {
perror(GPFIFO.c_str());
unlink(GPFIFO.c_str());
}
}
// For fprintf
if (NULL == (gp = popen("gnuplot 2> /tmp/gp1","w"))) {
perror("gnuplot");
pclose(gp);
}
// Redirect print
fprintf(gp, "set print \"%s\";\n", GPFIFO.c_str());
fflush(gp);
// For fscanf
if (NULL == (gpin = fopen(GPFIFO.c_str(),"r"))) {
perror(GPFIFO.c_str());
pclose(gp);
}
}
