.\"
.\" $Id: rfio_symlink.man,v 1.1 2005/03/31 13:13:03 baud Exp $
.\"
.\" @(#)$RCSfile: rfio_symlink.man,v $ $Revision: 1.1 $ $Date: 2005/03/31 13:13:03 $ CERN IT-PDP/DM Jean-Philippe Baud
.\" Copyright (C) 1999-2001 by CERN/IT/PDP/DM
.\" All rights reserved
.\"
.TH RFIO_SYMLINK 3 "$Date: 2005/03/31 13:13:03 $" LCG "Rfio Library Functions"
.SH NAME
rfio_symlink \- create a symbolic link to a file
.SH SYNOPSIS
.B #include <sys/types.h>
.br
\fB#include "rfio_api.h"\fR
.sp
.BI "int rfio_symlink (const char *" oldpath ", const char *" newpath ");"
.br
.BI "int rfio_msymlink (const char *" oldpath ", const char *" newpath ");"
.br
.BI "int rfio_msymlink_reset ();"
.br
.BI "int rfio_symend ();"
.SH DESCRIPTION
.B rfio_symlink
creates a symbolic link 
.I newpath
which contains the string
.IR oldpath .
.LP
.I newpath
may point to a non existing file.
.br
If
.I newpath
exists already, it will not be overwritten.
.br
Write permission is required on 
.I newpath
parent.
.LP
.B rfio_msymlink
is identical to
.B rfio_symlink
but keeps the connection open to the server unless there are more than MAXMCON
connections already opened. This is useful when issuing a series of symlink calls.
The last
.B rfio_msymlink
call should be followed by a call to
.BR rfio_symend .
.LP
.B rfio_msymlink_reset
is to be used when your program is forking. In such a case the permanent connections opened with
.B rfio_msymlink
become shared between the parent and the child. Use
.B rfio_msymlink_reset
to perform the necessary reset and close of the socket file descriptor in the parent or the child in order to be sure that only of them will receice an answer from the RFIO daemon.
.P
See NOTES section below.
.SH RETURN VALUE
This routine returns 0 if the operation was successful or -1 if the operation
failed. In the latter case,
.B serrno
is set appropriately.
.SH NOTES
Multiple connections using rfio_msymlink are thread-safe but not process-wide, therefore a forked child can share file descriptors opened with rfio_msymlink by its parent. Use
.B rfio_msymlink_reset
in such case.
.P
Multiple connections behaviour is undefined if you work in a multi-threaded environment and with threads \fBnot\fP created using the LCG's \fBCthread\fP interface.
.SH ERRORS
.TP 1.3i
.B ENOENT
A component of
.I newpath
prefix does not exist or
.I oldpath
is a null pathname.
.TP
.B ENOMEM
Insufficient memory.
.TP
.B EACCES
Search permission is denied on a component of the 
.I newpath
prefix or write permission on the 
.I newpath
parent directory is denied.
.TP
.B EFAULT
.I oldpath
or
.I newpath
is a NULL pointer.
.TP
.B EEXIST
.I newpath
already exists.
.TP
.B ENOTDIR
A component of the 
.I newpath
prefix is not a directory.
.TP
.B ENAMETOOLONG
The length of
.I oldpath
or
.I newpath
exceeds
.B CA_MAXPATHLEN
or the length of a path component exceeds
.BR CA_MAXNAMELEN .
.TP
.B SENOSHOST
Host unknown.
.TP
.B SENOSSERV
Service unknown.
.TP
.B SECOMERR
Communication error.
.TP
.B SEOPNOTSUP
Not supported on Windows.
.SH SEE ALSO
.BR Castor_limits(4) ,
.BR rfio_readlink(3) ,
.BR rfio_unlink(3) ,
.BR Cthread(3)
.SH AUTHOR
\fBLCG Grid Deployment\fP Team