'\" te
.\" Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
.TH rpc_svc_input 3NSL "23 Aug 2011" "SunOS 5.11" "Networking Services Library Functions"
.SH NAME
rpc_svc_input, svc_add_input, svc_remove_input \- declare or remove a callback on a file descriptor
.SH SYNOPSIS
.LP
.nf
#include <rpc/rpc.h>

\fBtypedef void (*\fR\fBsvc_callback_t\fR)(\fBsvc_input_id_t\fR \fIid\fR, \fBint\fR \fIfd\fR,
     \fBunsigned int\fR \fIevents\fR, \fBvoid *\fR\fIcookie\fR);
.fi

.LP
.nf
\fBsvc_input_id_t\fR \fBsvc_add_input\fR(\fBint\fR \fIfd\fR, \fBunsigned int\fR \fIrevents\fR,
     \fBsvc_callback_t\fR \fIcallback\fR, \fBvoid *\fR\fIcookie\fR);
.fi

.LP
.nf
\fBint\fR \fBsvc_remove_input\fR(\fBsvc_input_t\fR \fIid\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The following RPC routines are used to declare or remove a callback on a file descriptor.
.SS "Routines"
.sp
.LP
See \fBrpc\fR(3NSL) for the definition of the \fBSVCXPRT\fR data structure.
.sp
.ne 2
.mk
.na
\fBsvc_add_input\fB()\fR\fR
.ad
.RS 22n
.rt  
This function is used to register a \fIcallback\fR function on a file descriptor, \fIfd\fR. The file descriptor, \fIfd\fR, is the first parameter to be passed to \fBsvc_add_input()\fR. This \fIcallback\fR function will be automatically called if any of the events specified in the \fIevents\fR parameter occur on this descriptor. The \fIevents\fR parameter is used to specify when the callback is invoked. This parameter is a mask of poll events to which the user wants to listen. See \fBpoll\fR(2) for further details of the events that can be specified.
.sp
The callback to be invoked is specified using the \fIcallback\fR parameter. The \fIcookie\fR parameter can be used to pass any data to the \fIcallback\fR function. This parameter is a user-defined value which is passed as an argument to the \fIcallback\fR function, and it is not used by the Sun RPC library itself.
.sp
Several callbacks can be registered on the same file descriptor as long as each callback registration specifies a separate set of event flags.
.sp
The \fIcallback\fR function is called with the registration \fIid\fR, the \fIfd\fR file descriptor, an \fIrevents\fR value, which is a bitmask of all events concerning the file descriptor, and the \fIcookie\fR user-defined value.
.sp
Upon successful completion, the function returns a unique identifier for this registration, that can be used later to remove this callback. Upon failure, \fB-1\fR is returned and \fBerrno\fR is set to indicate the error.
.sp
The \fBsvc_add_input()\fR function will fail if: 
.sp
.ne 2
.mk
.na
\fB\fBEINVAL\fR\fR
.ad
.RS 10n
.rt  
The \fIfd\fR or \fIevents\fR parameters are invalid.
.RE

.sp
.ne 2
.mk
.na
\fB\fBEEXIST\fR\fR
.ad
.RS 10n
.rt  
A callback is already registered to the file descriptor with one of the specified events.
.RE

.sp
.ne 2
.mk
.na
\fB\fBENOMEM\fR\fR
.ad
.RS 10n
.rt  
Memory is exhausted.
.RE

.RE

.sp
.ne 2
.mk
.na
\fB\fBsvc_remove_input()\fR\fR
.ad
.RS 22n
.rt  
This function is used to unregister a callback function on a file descriptor, \fIfd\fR. The \fIid\fR parameter specifies the registration to be removed.
.sp
Upon successful completion, the function returns zero. Upon failure, \fB-1\fR is returned and \fBerrno\fR is set to indicate the error.
.sp
The \fBsvc_remove_input()\fR function will fail if: 
.sp
.ne 2
.mk
.na
\fBEINVAL\fR
.ad
.RS 10n
.rt  
The \fIid\fR parameter is invalid.
.RE

.RE

.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes: 
.sp

.sp
.TS
tab() box;
cw(2.75i) |cw(2.75i) 
lw(2.75i) |lw(2.75i) 
.
ATTRIBUTE TYPEATTRIBUTE VALUE
_
ArchitectureAll
_
Availabilitysystem/library
_
Interface StabilityCommitted
_
MT-LevelMT-Safe
.TE

.SH SEE ALSO
.sp
.LP
\fBpoll\fR(2), \fBrpc\fR(3NSL), \fBattributes\fR(5)