Hello. I’m writing a program that uses subprocess. This program invokes a.out to perform communication via standard I/O. The source code of a.out is in c.c. When I run this program, the program execution will block at line 10 of master.rkt. I don’t know how this happens. https://gist.github.com/elderica/8ab654f93ab2e9b4d43bdbdbbb1a223b

You may not want port->string ; I suspect that’s waiting on the port to close so it can read everything. Depending on the kind of response you are expecting, something like read or read-line may be better