Editando C5 - Introducción a C (sección)

= C5.5 Keywords and punctuation =
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The volatile keyword disables compiler optimization, forcing the compiler to fetch a new value each time. We will use volatile when defining I/O ports because the value of ports can change outside of software action. We will also use volatile when sharing a global variable between the main program and an interrupt service routine. It is a good programming practice not to use these keywords for your variable or function names.<br>
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Lists can also be used in general expressions. Sometimes it adds clarity to a program if related variables are modified at the same place. The value of a list of expressions is always the value of the last expression in the list. In the following example, first thetime is incremented, next thedate is decremented, and then x is set to k+2.

X = (thetime++, thedate--, k+2);
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