• via Digitalmars-d-bugs (28/28) Nov 14 2016 https://issues.dlang.org/show_bug.cgi?id=16686

via Digitalmars-d-bugs <digitalmars-d-bugs puremagic.com> writes:

https://issues.dlang.org/show_bug.cgi?id=16686

          Issue ID: 16686
           Summary: Can not spawn subprocess and read from File at same
                    time
           Product: D
           Version: D2
          Hardware: x86
                OS: Mac OS X
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: phobos
          Assignee: nobody puremagic.com
          Reporter: andrepuel gmail.com

Created attachment 1622
  --> https://issues.dlang.org/attachment.cgi?id=1622&action=edit
Script that reproduces the problem

In OSX, the implementation of the C function read() as well as the C function
fileno() will invoke flockfile on the given argument. The function
`spawnProcessImpl` from the `std.process` module tries to extract the fileno
from the three File that are passed (stdin, stdout and stderr), if one of this
files is busy doing read() in another thread, then the subprocess will not be
launched until the read() is fulfilled and the file is unlocked.

Attached is a simple code that demonstrates the issue. A read in stdin is done
in the main thread, while a secondary thread tries to execute a ls. Due to the
bug, the ls result will be available only after the user inputs a line in the
stdin.

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