Pipes between Python and C++ don't get closed -

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i spawning process in python using subprocess , want read output program using pipes. c++ program not seem close pipe though, when explicitly telling close.

#include <cstdlib> #include <ext/stdio_filebuf.h> #include <iostream>  int main(int argc, char **argv) {   int fd = atoi(argv[1]);   __gnu_cxx::stdio_filebuf<char> buffer(fd, std::ios::out);   std::ostream stream(&buffer);   stream << "hello world" << std::endl;   buffer.close();   return 0; }

i invoke small program python snippet:

import os                                                                                          import subprocess                                                                                   read, write = os.pipe()                                                                            proc = subprocess.popen(["./dummy", str(write)])                                                   data = os.fdopen(read, "r").read()                                                                 print data

the read() method not return, fd not closed. opening , closing write fd in python solves problem. seems hack me. there way close fd in c++ process?

thanks lot!

spawning child process on linux (all posix oses, really) accomplished via fork , exec. after fork, both processes have file open. c++ process closes it, file remains open until parent process closes fd also. normal code using fork, , handled wrapper around fork. read man page pipe. guess python has no way of knowing files being transferred child, though, , therefore doesn't know close in parent vs child process.


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