The behavior of a program is undefined when it uses the value of a pointer to a FILE object after the associated file is closed (see undefined behavior 148.) Programs that close the standard streams (especially stdout but also stderr and stdin) must be careful not to use the stream objects in subsequent function calls, particularly those that implicitly operate on such objects (such as printf(), perror(), and getc()).
This rule can be generalized to other representations of files, such as an int representing a POSIX file descriptor that has been passed to close()..
Noncompliant Code Example
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