popen doesn't work on Windows #4843
Description
Environment
Provide at least:
Windows 10 64bit
jruby 9.1.14.0 (2.3.3) 2017-11-08 2176f24 Java HotSpot(TM) Client VM 25.144-b01 on 1.8.0_144-b01 +jit [mswin32-x86]
Expected Behavior
In jruby 9.1.13, this command outputs "a"
/cygdrive/c/jruby-9.1.13.0/bin/jruby.exe -e 'io = IO.popen("cat", "r+"); io.puts("a");p io.read(1)'
"a"
Actual Behavior
In jruby 9.1.14, no return
/cygdrive/c/jruby-9.1.14.0/bin/jruby.exe -e 'io = IO.popen("cat", "r+"); io.puts("a");p io.read(1)'
On Linux, it returns "a"
./jruby-9.1.14.0/bin/jruby -e 'io = IO.popen("cat", "r+"); io.puts("a");p io.read(1)'
"a"