'\" t
.\"     Title: modbus_reply
.\"    Author: [see the "AUTHORS" section]
.\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
.\"      Date: 10/18/2014
.\"    Manual: Libmodbus Manual
.\"    Source: libmodbus 3.0.6
.\"  Language: English
.\"
.TH "MODBUS_REPLY" "3" "10/18/2014" "libmodbus 3\&.0\&.6" "Libmodbus Manual"
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.SH "NAME"
modbus_reply \- send a reponse to the received request
.SH "SYNOPSIS"
.sp
*int modbus_reply(modbus_t *\fIctx\fR, const uint8_t *\fIreq\fR, int \fIreq_length\fR, modbus_mapping_t *\fImb_mapping\fR);
.SH "DESCRIPTION"
.sp
The \fImodbus_reply()\fR function shall send a response to received request\&. The request \fIreq\fR given in argument is analyzed, a response is then built and sent by using the information of the modbus context \fIctx\fR\&.
.sp
If the request indicates to read or write a value the operation will done in the modbus mapping \fImb_mapping\fR according to the type of the manipulated data\&.
.sp
If an error occurs, an exception response will be sent\&.
.sp
This function is designed for Modbus server\&.
.SH "RETURN VALUE"
.sp
The \fImodbus_reply()\fR function shall return the length of the response sent if successful\&. Otherwise it shall return \-1 and set errno\&.
.SH "ERRORS"
.PP
EMBMDATA
.RS 4
Sending has failed
.RE
.sp
See also the errors returned by the syscall used to send the response (eg\&. send or write)\&.
.SH "SEE ALSO"
.sp
\fBmodbus_reply_exception\fR(3) \fBlibmodbus\fR(7)
.SH "AUTHORS"
.sp
The libmodbus documentation was written by St\('ephane Raimbault <\m[blue]\fBstephane\&.raimbault@gmail\&.com\fR\m[]\&\s-2\u[1]\d\s+2>
.SH "NOTES"
.IP " 1." 4
stephane.raimbault@gmail.com
.RS 4
\%mailto:stephane.raimbault@gmail.com
.RE