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Receiving input from a stream directly following an output to that stream without an intervening call to fflush(), fseek(), fsetpos(), or rewind(), or outputting to a stream after receiving input from it without a call to fseek(), fsetpos(), rewind() if the file is not at end-of-file results in undefined behavior. Consequently, a call to fseek(), fflush() or fsetpos() is necessary between input and output to the same stream (see FIO07-C. Prefer fseek() to rewind()).
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Noncompliant Code Example
The following non-compliant noncompliant code example appends data to a file and then reads from the same file.
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