'\" t
.\"     Title: modbus_receive_confirmation
.\"    Author: [see the "AUTHORS" section]
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: 02/28/2020
.\"    Manual: libmodbus Manual
.\"    Source: libmodbus v3.1.6
.\"  Language: English
.\"
.TH "MODBUS_RECEIVE_CONFI" "3" "02/28/2020" "libmodbus v3\&.1\&.6" "libmodbus Manual"
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.SH "NAME"
modbus_receive_confirmation \- receive a confirmation request
.SH "SYNOPSIS"
.sp
\fBint modbus_receive_confirmation(modbus_t *\fR\fB\fIctx\fR\fR\fB, uint8_t *\fR\fB\fIrsp\fR\fR\fB);\fR
.SH "DESCRIPTION"
.sp
The \fBmodbus_receive_confirmation()\fR function shall receive a request via the socket of the context \fIctx\fR\&. This function must be used for debugging purposes because the received response isn\(cqt checked against the initial request\&. This function can be used to receive request not handled by the library\&.
.sp
The maximum size of the response depends on the used backend, in RTU the \fIrsp\fR array must be \fIMODBUS_RTU_MAX_ADU_LENGTH\fR bytes and in TCP it must be \fIMODBUS_TCP_MAX_ADU_LENGTH\fR bytes\&. If you want to write code compatible with both, you can use the constant \fIMODBUS_MAX_ADU_LENGTH\fR (maximum value of all libmodbus backends)\&. Take care to allocate enough memory to store responses to avoid crashes of your server\&.
.SH "RETURN VALUE"
.sp
The function shall store the confirmation request in \fIrsp\fR and return the response length if sucessful\&. The returned request length can be zero if the indication request is ignored (eg\&. a query for another slave in RTU mode)\&. Otherwise it shall return \-1 and set errno\&.
.SH "EXAMPLE"
.sp
.if n \{\
.RS 4
.\}
.nf
uint8_t rsp[MODBUS_MAX_ADU_LENGTH];
rc = modbus_receive_confirmation(ctx, rsp);
.fi
.if n \{\
.RE
.\}
.SH "SEE ALSO"
.sp
\fBmodbus_send_raw_request\fR(3)
.SH "AUTHORS"
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The libmodbus documentation was written by Stéphane Raimbault <stephane\&.raimbault@gmail\&.com>