# Command: setNONBLOCK

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Name:

    setNONBLOCK - Switch between blocking and non-blocking I/O.

Synopsis:

    ifstream {true|false} setNONBLOCK -> ifstream

Examples:

    cin   false setNONBLOCK
      myfifo true  setNONBLOCK % set non-blocking I/O for my fifo.

Description:

    "setNONBLOCK" sets or erases the O_NONBLOCK flag on
      an input stream. The O_NONBLOCK flag determines, if
      a read attempt will block when no data is currently
      available from the stream. By default, a newly
      created stream has the O_NONBLOCK-Flag erased,
      meaning that blocking I/O is selected. By erasing
      O_NONBLOCK, a subsequent read attempt on the stream
      will yield EOF if no data is available.

      Alternatives: Function setNONBLOCK_is_b (undocumented)
      -> behavior and synopsis are the same.

Parameters:

    In : ifstream: The stream to change the flag on.
      Out:	-

Bugs:

    -

Diagnostics:

    If a system-error occurs, a code is stored in "sys_errno"
      (contained in errordict) to identify the error, and "sys_errname"
      is set to the error message. Then a "SystemError" is raised.
      The following system errors may be issued, according to the
      POSIX standard (errors in parentheses are not
      expected to occur in this routines' context):

      (EACCES)  Search permission is denied for a
      directory in a files path prefix.
      (EAGAIN)  The ON_NONBLOCK flag is set for a file
      descriptor and the process would be
      delayed in the I/O operation.
      EBADF   Invalid file descriptor. (With the current
      implementation, this indicates trouble
      getting a filedescriptor from a stream. If
      it occurs, ask the author for a proper
      solution!)
      (EDEADLK) An fcntl with function F_SETLKW would
      cause a deadlock.
      EINTR   Function was interrupted by a signal.
      (EINVAL)  Invalid argument.
      (EMFILE   Too many file descriptors are in use by
      this process.
      (ENOLCK)  No locks available.

Author:

    R Kupper

FirstVersion:

    Oct 20 1999

SeeAlso:

- available
- ignore

Source:

    /opt/conda/conda-bld/nest_1524088722951/work/nest-2.14.0/sli/processes.h

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