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Publishing to a topic via subscriber callback function

Hello, I am wondering if anybody could help me with this problem. I have a listener that just publishes to a topic when another topic is published data, so basically the topic it is listening on gets data published. I have tried putting global variable in the code whose change can map into the main function but ros is not allowing global variables. I also tried to define the nodehandle as global but ros is not allowing this either. (I think before rosinit no ros components will be recognized). My code is in C++. Any help as to what could be done would be really appreciated. I am including a basic skeleton of the code I am trying: void func_cb(std_msgs type param as defined in ros chatter example) { //need some code here to publish to a topic //problem:nodehandle out of scope,cannot define new nodehandle } int main(... ) { //ros initilization //ros node handle initialization //ros subscription initialization //callback spinner return 0; }

Publishing to a topic via subscriber callback function

Hello, I am wondering if anybody could help me with this problem. I have a listener that just publishes to a topic when another topic is published data, so basically the topic it is listening on gets data published. I have tried putting global variable in the code whose change can map into the main function but ros is not allowing global variables. I also tried to define the nodehandle as global but ros is not allowing this either. (I think before rosinit no ros components will be recognized). My code is in C++. Any help as to what could be done would be really appreciated. I am including a basic skeleton of the code I am trying: trying:

void func_cb(std_msgs type param as defined in ros chatter example) { example)

{

//need some code here to publish to a topic

//problem:nodehandle out of scope,cannot define new nodehandle }

}

int main(... ) { )

{

//ros initilization initilization

//ros node handle initialization initialization

//ros subscription initialization initialization

//callback spinner spinner

return 0; 0;

}

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Publishing to a topic via subscriber callback function

Hello, I am wondering if anybody could help me with this problem. I have a listener that just publishes to a topic when another topic is published data, so basically the topic it is listening on gets data published. I have tried putting global variable in the code whose change can map into the main function but ros is not allowing global variables. I also tried to define the nodehandle as global but ros is not allowing this either. (I think before rosinit no ros components will be recognized). My code is in C++. Any help as to what could be done would be really appreciated. I am including a basic skeleton of the code I am trying:

void func_cb(std_msgs type param as defined in ros chatter example)

{

//need example) { //*need some code here to publish to a topic

//problem:nodehandle topic* //*problem:nodehandle out of scope,cannot define new nodehandle

}

nodehandle* } int main(... )

{

) { //ros initilization

initilization //ros node handle initialization

initialization //ros subscription initialization

initialization //callback spinner

spinner return 0;

}

0; }