'\" te
.\" Copyright (c) 2003, Sun Microsystems, Inc.,  All Rights Reserved
.TH ldi_putmsg 9F "3 June 2003" "SunOS 5.11" "Kernel Functions for Drivers"
.SH NAME
ldi_putmsg, ldi_getmsg \- Read/write message blocks from/to a stream
.SH SYNOPSIS
.LP
.nf
#include <sys/sunldi.h>

\fBint\fR \fBldi_putmsg\fR(\fBldi_handle_t\fR\fI lh\fR, \fBmblk_t *\fR\fIsmp\fR);
.fi

.LP
.nf
\fBint\fR \fB ldi_getmsg\fR(\fBldi_handle_t\fR \fIlh\fR, \fBmblk_t **\fR\fIrmp\fR, \fBtimestruc_t *\fR\fItimeo\fR);
.fi

.SH PARAMETERS
.sp
.ne 2
.mk
.na
\fB\fIlh\fR \fR
.ad
.RS 10n
.rt  
Layered handle.
.RE

.sp
.ne 2
.mk
.na
\fB\fIsmp\fR \fR
.ad
.RS 10n
.rt  
Message block to send.
.RE

.sp
.ne 2
.mk
.na
\fB\fIrmp\fR \fR
.ad
.RS 10n
.rt  
Message block to receive.
.RE

.sp
.ne 2
.mk
.na
\fB\fItimeo\fR \fR
.ad
.RS 10n
.rt  
Optional timeout for data reception.
.RE

.SH DESCRIPTION
.sp
.LP
The \fBldi_putmsg\fR function allows a caller to send a message block to a streams device specified by the layered handle \fIlh\fR. Once the message (smp) has been passed to \fBldi_putmsg()\fR, the caller must not free the message even if an error occurs.
.sp
.LP
The \fBldi_getmsg()\fR function allows a caller to receive a message block from a streams device specified by the layered handle \fIlh\fR. Callers must free the message received with \fBfreemsg\fR(9F).
.sp
.LP
If a NULL timeout value is specified when the caller receives a message, the caller sleeps until a message is received.
.SH RETURN VALUES
.sp
.LP
The \fBldi_putmsg()\fR and \fBldi_getmsg()\fR functions return \fB0\fR upon success. If a failure occurs before the request is passed to the device, the possible return values are shown below. Otherwise any other error number may be returned by the device.
.sp
.ne 2
.mk
.na
\fBEINVAL\fR
.ad
.RS 11n
.rt  
Invalid input parameters.
.RE

.sp
.ne 2
.mk
.na
\fBENOTSUP\fR
.ad
.RS 11n
.rt  
Operation is not supported for this device.
.sp
The \fBldi_getmsg()\fR function may also return:
.sp
.ne 2
.mk
.na
\fBETIME\fR
.ad
.RS 9n
.rt  
Returned if the timeout \fBtimeo\fR expires with no messages received.
.RE

.RE

.SH CONTEXT
.sp
.LP
These functions may be called from user or kernel context.