[metadata]
id = "FIO42-C"
type = "recommendation"
category = "FIO"
number = 42
title = "Close files when they are no longer needed"
description = """
A call to thefopen()orfreopen()function must be matched with a call
tofclose()before the lifetime of the last pointer that stores the return value
of the call has ended or before normal program termination, whichever occurs
first. In general, this rule should also be applied to other functions with open
and close resources, such as the POSIXopen()andclose()functions, or the
Microsoft WindowsCreateFile()andCloseHandle()functions. This code example is
noncompliant because the file opened by the call tofopen()is not closed before
functionfunc()returns:
"""
severity = "Medium"
likelihood = "Unlikely"
priority = "P2"
level = "L3"
cert_version = "2016 Edition (Wiki)"
last_modified = "Aug 06, 2025"
[rules.cert_c.FIO42-C]
enabled = true
[references]
wiki = "https://wiki.sei.cmu.edu/confluence/display/c/FIO42-C.+Close+files+when+they+are+no+longer+needed"
cwe = ["CWE-404", "CWE-459", "CWE-772", "CWE-773", "CWE-775", "CWE-403", "CWE-771"]