Things Not To Do with Files in C Programming

Do Not Forget To Check If The File Opened Successfully



Always check the return value of fopen to ensure the file was opened successfully. If it returns NULL, handle the error appropriately to prevent undefined behavior.

Do Not Neglect To Close Files



Forgetting to close files can lead to resource leaks, as open file descriptors are a limited resource in an operating system. Always ensure files are closed after operations are completed.

Do Not Use Hard-Coded File Paths



Using hard-coded file paths reduces the portability of your code and can lead to errors if the file structure changes. Use relative paths or configuration options to specify file paths.

Do Not Ignore The Return Value Of Fread/fwrite



Ignoring the return value of fread or fwrite can lead to undetected errors in reading from or writing to a file. Always check the return value to ensure the expected number of bytes were processed.

Do Not Assume File Structure



Assuming a specific file structure without validation can lead to parsing errors and undefined behavior. Always validate the file structure before processing its contents.

Do Not Forget To Handle End-of-File (EOF) Properly



Reading from a file without checking for EOF can lead to infinite loops or reading invalid data. Always handle EOF properly in file reading loops.

Do Not Use Fscanf Without Checking For Successful Matches



Using fscanf without checking the return value can lead to using uninitialized variables if the expected data is not present in the file. Always check that the expected number of items were matched.