Pls Help expression cannot be used as a function

[girecs]

String httpRequestData = "api_key=" + apiKeyValue + "&sensor=" + sensorName + "&location=" + sensorLocation + "&value1=" + String(mpu.temperature());

I cant compile it. It says "expression cannot be used as a function". Can anyone help me

[guix]

Welcome

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[J-M-L]

Possibly (if there error is really there) use

String httpRequestData;

httpRequestData.reserve(50); // give a size that makes sense to prevent too many alloc requests when building€ up the request

httpRequestData = "api_key=";
httpRequestData += apiKeyValue;
httpRequestData += "&sensor=";
httpRequestData += sensorName;
httpRequestData += "&location=";
httpRequestData += sensorLocation;
httpRequestData += "&value1=";
httpRequestData += String(mpu.temperature(), 2); // 2 digits after decimal point

It’s more robust to use += as it will support more data types and not confuse things with precedence of C++ types and operations
But may be there is no need to build up the URL and you can send it piece by piece…

[johnwasser]

@girecs

String( mpu.temperature() );

You are using "mpu.temperature" as a function. IS it a function? Check the documentation or source.

[girecs]

Thank you, I will try it

[girecs]

Thank you, I will look it up and try it