In my C++ code, this worked (on mac OsX mavericks, using g++ Apple LLVM version 5.0):
#include
#include
...
// ready to make a plot
pid_t childpid=fork();
if(childpid==0) {
// child process makes plot
std::FILE* pipehandle=popen("gnuplot -persist","w");
// make some plot. You can send multiple commands to the pipe each ending in \n
std::fprintf(pipehandle,"plot \"results.txt\" using 1:2 with lines\n");
std::fprintf(pipehandle,"quit\n");
std::fflush(pipehandle);
std::fclose(pipehandle);
// child process exits
exit(0);
}
// parent process waits for child process to exit
waitpid(childpid,NULL,0);
// you can now repeat to make other gnuplots; all will appear simultaneously in the
// terminal and are persistent after the parent process has finished.
