[Python-checkins] CVS: python/dist/src/Doc/lib libfcntl.tex,1.23,1.24

[Barry Warsaw]

Update of /cvsroot/python/python/dist/src/Doc/lib
In directory usw-pr-cvs1:/tmp/cvs-serv8309

Modified Files:
	libfcntl.tex 
Log Message:
Provide a much better (and complete!) description of the lockf()
function, based on an eyeballing of the code.


Index: libfcntl.tex
===================================================================
RCS file: /cvsroot/python/python/dist/src/Doc/lib/libfcntl.tex,v
retrieving revision 1.23
retrieving revision 1.24
diff -C2 -r1.23 -r1.24
*** libfcntl.tex	2000/08/02 20:53:51	1.23
--- libfcntl.tex	2001/01/25 00:36:54	1.24
***************
*** 54,61 ****
  \end{funcdesc}
  
! \begin{funcdesc}{lockf}{fd, code, \optional{len, \optional{start, \optional{whence}}}}
! This is a wrapper around the \constant{FCNTL.F_SETLK} and
! \constant{FCNTL.F_SETLKW} \function{fcntl()} calls.  See the \UNIX{}
! manual for details.
  \end{funcdesc}
  
--- 54,95 ----
  \end{funcdesc}
  
! \begin{funcdesc}{lockf}{fd, operation,
!     \optional{len, \optional{start, \optional{whence}}}}
! This is essentially a wrapper around the \function{fcntl()} locking
! calls.  \var{fd} is the file descriptor of the file to lock or unlock,
! and \var{operation} is one of the following values:
! 
! \begin{itemize}
! \item \constant{LOCK_UN} -- unlock
! \item \constant{LOCK_SH} -- acquire a shared lock
! \item \constant{LOCK_EX} -- acquire an exclusive lock
! \end{itemize}
! 
! When \var{operation} is \constant{LOCK_SH} or \constant{LOCK_EX}, it
! can also be bit-wise OR'd with \constant{LOCK_NB} to avoid blocking on
! lock acquisition.  If \constant{LOCK_NB} is used and the lock cannot
! be acquired, an \exception{IOError} will be raised and the exception
! will have an \var{errno} attribute set to \constant{EACCES} or
! \constant{EAGAIN} (depending on the operating system; for portability,
! check for both values).
! 
! \var{length} is the number of bytes to lock, \var{start} is the byte
! offset at which the lock starts, relative to \var{whence}, and
! \var{whence} is as with \function{fileobj.seek()}, specifically:
! 
! \begin{itemize}
! \item \constant{0} -- relative to the start of the file
!       (\constant{SEEK_SET})
! \item \constant{1} -- relative to the current buffer position
!       (\constant{SEEK_CUR})
! \item \constant{2} -- relative to the end of the file
!       (\constant{SEEK_END})
! \end{itemize}
! 
! The default for \var{start} is 0, which means to start at the
! beginning of the file.  The default for \var{length} is 0 which means
! to lock to the end of the file.  The default for \var{whence} is also
! 0.
! 
  \end{funcdesc}