getc() vs fgetc() – What are the major differences?

From the Advanced Programming in Unix Environment:

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The difference between getc and fgetc is that getc can be
implemented as a macro, whereas fgetc cannot be implemented as a
macro. This means three things:

• The argument to getc should not be an expression with side effects.
• Since fgetc is guaranteed to be a function, we can take its address. This allows us to pass the address of fgetc as an argument
  to another function.
• Calls to fgetc probably take longer than calls to getc, as it usually takes more time to call a function.

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