[metadata]
id = "EXP30-C"
type = "rule"
category = "EXP"
number = 30
title = "Do not depend on the order of evaluation for side effects"
description = """
Evaluation of an expression may produceside effects. At specific points during
execution, known assequence points, all side effects of previous evaluations are
complete, and no side effects of subsequent evaluations have yet taken place. Do
not depend on the order of evaluation for side effects unless there is an
intervening sequence point. The C Standard, 6.5, paragraph 2 [ISO/IEC
9899:2024], states This requirement must be met for each allowable ordering of
the subexpressions of a full expression; otherwise, the behavior isundefined.
(Seeundefined behavior 34.)
"""
severity = "Medium"
likelihood = "Probable"
priority = "P8"
level = "L2"
cert_version = "2016 Edition (Wiki)"
last_modified = "Aug 06, 2025"
[rules.cert_c.EXP30-C]
enabled = true
[references]
wiki = "https://wiki.sei.cmu.edu/confluence/display/c/EXP30-C.+Do+not+depend+on+the+order+of+evaluation+for+side+effects"
cwe = ["CWE-758"]