setNONBLOCK


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: Source:
/home/graber/work-nest/nest-git/nest-simulator/sli/processes.h