I managed to get the previous issue sorted. You guys were right,
FIFOs are blocking, so you first need to open a read before you can
start writing to it. Now I just have a question. How do I read this
data in C++? At the moment I am using

double *buf = new double;

FILE* fifo = fopen(“myfifo”,“rb”);
for (j=0;j<500000;j++)

to read it out. Inside the for loop, I copy buf to an array. This
doesn’t work. When I write the received data to a datafile, open it
in Matlab and plot it, I get all-zeros. When I output the first 100
values on the shell, they are in the order of 1e-314. Can anyone
please tell me how to do this?

Thank you very much.