.TH "MQTTClient_willOptions" 3 "Sat Aug 16 2025 14:15:23" "Paho MQTT C Client Library" \" -*- nroff -*-
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.SH NAME
MQTTClient_willOptions
.SH SYNOPSIS
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.PP
.PP
\fR#include <MQTTClient\&.h>\fP
.SS "Data Fields"

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.RI "char \fBstruct_id\fP [4]"
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.RI "int \fBstruct_version\fP"
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.RI "const char * \fBtopicName\fP"
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.RI "const char * \fBmessage\fP"
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.RI "int \fBretained\fP"
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.RI "int \fBqos\fP"
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.RI "struct {"
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.RI "   int \fBlen\fP"
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.RI "   const void * \fBdata\fP"
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.RI "} \fBpayload\fP"
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.SH "Detailed Description"
.PP 
\fBMQTTClient_willOptions\fP defines the MQTT "Last Will and Testament" (LWT) settings for the client\&. In the event that a client unexpectedly loses its connection to the server, the server publishes the LWT message to the LWT topic on behalf of the client\&. This allows other clients (subscribed to the LWT topic) to be made aware that the client has disconnected\&. To enable the LWT function for a specific client, a valid pointer to an \fBMQTTClient_willOptions\fP structure is passed in the \fBMQTTClient_connectOptions\fP structure used in the \fBMQTTClient_connect()\fP call that connects the client to the server\&. The pointer to \fBMQTTClient_willOptions\fP can be set to NULL if the LWT function is not required\&. 
.SH "Field Documentation"
.PP 
.SS "char struct_id[4]"
The eyecatcher for this structure\&. must be MQTW\&. 
.SS "int struct_version"
The version number of this structure\&. Must be 0 or 1 0 means there is no binary payload option 
.SS "const char* topicName"
The LWT topic to which the LWT message will be published\&. 
.SS "const char* message"
The LWT payload in string form\&. 
.SS "int retained"
The retained flag for the LWT message (see \fBMQTTClient_message\&.retained\fP)\&. 
.SS "int qos"
The quality of service setting for the LWT message (see \fBMQTTClient_message\&.qos\fP and \fBQuality of service\fP)\&. 
.SS "int len"
binary payload length 
.SS "const void* data"
binary payload data 
.SS "struct  { \&.\&.\&. }  payload"
The LWT payload in binary form\&. This is only checked and used if the message option is NULL 

.SH "Author"
.PP 
Generated automatically by Doxygen for Paho MQTT C Client Library from the source code\&.