The ISO/IEC 9899-1999 C standard function fopen() is typically used to open an existing file or create a new one. However, fopen() does not provide a mechanism to determine if an existing file has been opened or a new file has been created. This may lead to a program overwriting or accessing an unintended file.
Non-Compliant Code Example
In this example, a file name is supplied to fopen() to create and open for writing. However, there is no guarantee that the file referenced by file_name does not exist prior to calling fopen(). This may cause an unintended file to be accessed or overwritten.
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