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The following scenarios can result in undefined behavior 151:

•  Receiving input from a stream directly following an output to that stream without an intervening call to fflush(), fseek(), fsetpos(), or rewind() if the file is not at end-of-file
•  Outputting to a stream after receiving input from that stream without a call to fseek(), fsetpos(), or rewind() if the file is not at end-of-file

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Consequently, a call to fseek(), fflush(), or fsetpos() is necessary between input and output to the same stream

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(

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see FIO07-C. Prefer fseek() to rewind().)

Noncompliant Code Example

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