I have been using Mosquitto.h on another program within the Raspberry Pi 4 with no issues. I recently purchased an Allied Vision camera that uses the VimbaX SDK. In trying to add the #include <mosquitto.h> and my MQTT code from another program I started to get errrors as below. I have confirmed that the code found the include because if I change the name, for example mosquittoa.h then I get an error. I enclose a portion of the code and the resultant error. I would appreciate some assistance in this problem.
********* The errors during compilation **********
Scanning dependencies of target AsynchronousGrab_VmbCPP
[ 33%] Building CXX object AsynchronousGrab/CMakeFiles/AsynchronousGrab_VmbCPP.dir/AcquisitionHelper.cpp.o
[ 66%] Linking CXX executable AsynchronousGrab_VmbCPP
/usr/bin/ld: CMakeFiles/AsynchronousGrab_VmbCPP.dir/AcquisitionHelper.cpp.o: in function VmbCPP::Examples::mqtt_send(char*)': AcquisitionHelper.cpp:(.text+0x4c): undefined reference to mosquitto_publish’
/usr/bin/ld: CMakeFiles/AsynchronousGrab_VmbCPP.dir/AcquisitionHelper.cpp.o: in function VmbCPP::Examples::message_callback(mosquitto*, void*, mosquitto_message const*)': AcquisitionHelper.cpp:(.text+0x13c): undefined reference to mosquitto_topic_matches_sub’
collect2: error: ld returned 1 exit status
make[2]: *** [AsynchronousGrab/CMakeFiles/AsynchronousGrab_VmbCPP.dir/build.make:120: AsynchronousGrab/AsynchronousGrab_VmbCPP] Error 1
make[1]: *** [CMakeFiles/Makefile2:176: AsynchronousGrab/CMakeFiles/AsynchronousGrab_VmbCPP.dir/all] Error 2
make: *** [Makefile:103: all] Error 2
A portion of my applicable code …
//****mqtt code ******
#include <signal.h>
#include <stdint.h>
#include <mosquitto.h>
//****mqtt code ******
…
namespace VmbCPP {
namespace Examples {
//*************************************************************
//mqtt code ***********************************************
//*********************************************************
int mqtt_send(char *msg){
return mosquitto_publish(mosq, NULL, topic, strlen(msg), msg, 0, 0);
}
void handle_signal(int s)
{
run = 0;
}
void connect_callback(struct mosquitto *mosq, void *obj, int result)
{
LOG(“10000:connect callback, rc=%d\n”, result);
}
void message_callback(struct mosquitto *mosq, void *obj, const struct mosquitto_message *message)
{
bool match = 0;
//char *buf = malloc(64);
char *buf;
buf = (char *) malloc(64);
char ABbuf = “ABCDEFGHIJKLMN”;
char command = “xxxx”; //capture the command here
char Instruction =“T”; //this is used to capture the instruction sent over
char *ret;
//printf("ABC message '%.s’ for topic ‘%s’\n", message->payloadlen, (char) message->payload, message->topic);
//mosquitto_topic_matches_sub("/devices/wb-adc/controls/+", message->topic, &match);
mosquitto_topic_matches_sub("testTopic", message->topic, &match);
}
//*************************************************************
//mqtt code END *******************************************
//*********************************************************
…
} // namespace Examples
} // namespace VmbCPP