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diff --git a/source/arduino/static.rst b/source/arduino/static.rst deleted file mode 100644 index 01f3dbf..0000000 --- a/source/arduino/static.rst +++ /dev/null @@ -1,57 +0,0 @@ -.. highlight:: cpp - -.. _arduino-static: - -Static -====== - -The ``static`` keyword can be used to create variables that are -visible to only one function. However, unlike local variables that get -created and destroyed every time a function is called, ``static`` -variables persist beyond the function call, preserving their data -between function calls. - -Variables declared as ``static`` will only be created and initialized -the first time a function is called. - -.. note:: This is only one use of the ``static`` keyword in C++. It - has some other important uses that are not documented here; consult - a reliable C++ reference for details. - -Example -------- - -One use case for ``static`` variables is implementing counters that -last longer than the functions which need them, but shouldn't be -shared to other functions. Here's an example:: - - void setup() { - SerialUSB.begin(); - } - - void loop() { - int reading; - if (timeToReadSensors()) { - reading = readSensors(); - } - // do something with reading - } - - int readSensors() { - static int numSensorReadings = 0; - numSensorReadings++; - if (numSensorReadings % 100 == 0) { - SerialUSB.print("just got to another 100 sensor readings"); - } - return analogRead(...); - } - -In this example, the static variable ``numSensorReadings`` is -initialized to zero the first time ``readSensors()`` is called, and -then incremented, so it starts out at one. Subsequent calls to -``readSensors()`` won't reset ``numSensorReadings`` to zero, because -it was declared ``static``. Thus, ``numSensorReadings`` is a count of -the number of times that ``readSensors()`` has been called. - - -.. include:: cc-attribution.txt |