CONCURRENCY.MAA : Multiple Accesses of Atomic

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C and C++

CONCURRENCY.MAA : Multiple Accesses of Atomic

要旨

A given atomic variable is accessed two or more times in the same expression.

プロパティ

クラス名

Multiple Accesses of Atomic

日本語クラス名

Multiple Accesses of Atomic

クラス分類

信頼性 (reliability)

ニーモニック

CONCURRENCY.MAA

カテゴリー

CERT-C	CERT-C:CON32-C	Prevent data races when accessing bit-fields from multiple threads
	CERT-C:CON40-C	Do not refer to an atomic variable twice in an expression
	CERT-C:CON43-C	Do not allow data races in multithreaded code
	CERT-C:POS49-C	When data must be accessed by multiple threads, provide a mutex and guarantee no adjacent data is also accessed

対応言語

C および C++ で利用可能です。

有効/無効設定

このワーニングクラスのチェックはデフォルトで無効になっており、プロジェクトには非正規の C向けAST が必要になります。有効にするにはプロジェクト設定ファイル（configuration file）に以下の WARNING_FILTER ルールと RETAIN_UNNORMALIZED_C_AST 設定を追加してください。

RETAIN_UNNORMALIZED_C_AST = Yes
WARNING_FILTER += allow class="Multiple Accesses of Atomic"

注：非正規化された AST を継続して使用した場合、使用ディスク容量が増加し解析時間が長くなる可能性があります。

例

#include <stdatomic.h>

atomic_int atomic_var = 0;
atomic_int other_atomic_var = 1;
int not_atomic_var = 0;

int compute_sums(void){
    int i = 0;
    atomic_var += 1;                              /* ok: += is guaranteed atomic by standard */
    atomic_var = atomic_var + 1;  /* 'Multiple Accesses of Atomic' warning issued here */
    i += atomic_var + atomic_var; /* 'Multiple Accesses of Atomic' warning issued here */
    atomic_var + other_atomic_var;                /* ok: each atomic variable is only accessed once */
    i += not_atomic_var + not_atomic_var;         /* ok: not an atomic variable */
    return i;
}

CONCURRENCY.MAA : Multiple Accesses of Atomic

要旨

プロパティ

例

関連のある設定ファイルパラメータ