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Arduino IDE 1.x
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'dtostrf' was not declared in this scope - Zero and DUE, but works for UNO, Yun and ATMEGA2560 #3411

Closed ad5jo closed 9 years ago

ad5jo commented 9 years ago

Hello, Please will someone add this function for the (was ONE, now corrected) Zero and DUE boards? 'dtostrf' was not declared in this scope Thank you, Dave void loop() { // put your main code here, to run repeatedly: // Convert_float_to_String or Double_to_String float floatVar = 9.876543; int minStringWidthIncDecimalPoint = 16; int numVarsAfterDecimal = 8; static char charBuf[16]; String sVal; dtostrf(floatVar, minStringWidthIncDecimalPoint, numVarsAfterDecimal, charBuf); //dtostrf(floatVar,16, 8, charBuf); sVal = String(charBuf); }

matthijskooijman commented 9 years ago

What is the ONE exactly? On the Arduino Uno, the code you pasted works as-is in git master (1.6.5-ish). On the Due, it doesn't, but adding #include <avr/dtostrf.h> fixes this.

Also, dtostrf is not part of the supported Arduino API. It is offered by avr-libc, but not libc on other architectures. On the Due, there is a dtostrf.h for compatibility, really intended for the String class. You can use it as well, but it's not part of the supported API.

The standard way to parse floats using the supported Arduino API is to use String::parseFloat (IIRC) method. If you want a portable sketch, use that. Otherwise you will have to use #ifdefs to figure out the current platform and whether dtostrf is available and where.

ad5jo commented 9 years ago

Hi matthijskooijman, Thank you! The 'ONE' was a mistake. I meant Zero. Sorry. This is the URL: http://www.arduino.cc/en/Main/ArduinoBoardZero

Adding #include < avr/dtostrf.h > fixes my problem. I tried to look for String::parseFloat but I didn't see anything related to Arduino. I also looked here: http://www.arduino.cc/en/Reference/StringObject Many Arduino user's have looked for a way to convert String to Float. Can you provide a URL for String::parseFloat so I can convert a string to a float in a "Standard" way ?

matthijskooijman commented 9 years ago

Ah, my bad, it is called String::toFloat().

john-espina commented 6 years ago

@matthijskooijman cheers! this fixed my problem too! Added #include <avr/dtostrf.h> to the Adafruit_MQTT.cpp file

emanavas commented 5 years ago

Thanks. works great!

baqwas commented 4 years ago

What is the "official" solution for the MKR boards, please?