LANG.STRUCT.UCTCH : Unreachable Catch

An exception handler will never be executed because an earlier handler catches all its exceptions.

There are three possible cases.

A handler for some type C occurs earlier than a handler for a type D that is derived from C.

A handler for void* occurs earlier than a handler for some other pointer type.

An ellipsis catch handler catch(...) occurs earlier than another handler.

プロパティ

クラス名

Unreachable Catch

日本語クラス名

Unreachable Catch

クラス分類

冗長性 (redundancy)

ニーモニック

LANG.STRUCT.UCTCH

カテゴリー

AUTOSARC++14	AUTOSARC++14:M15-3-6	Where multiple handlers are provided in a single try-catch statement or function-try-block for a derived class and some or all of its bases, the handlers shall be ordered most-derived to base class.
	AUTOSARC++14:M15-3-7	Where multiple handlers are provided in a single try-catch statement or function-try-block, any ellipsis (catch-all) handler shall occur last.
MisraC++2008	MisraC++2008:15-3-6	Where multiple handlers are provided in a single try-catch statement or function-try-block for a derived class and some or all of its bases, the handlers shall be ordered most-derived to base class.
	MisraC++2008:15-3-7	Where multiple handlers are provided in a single try-catch statement or function-try-block, any ellipsis (catch-all) handler shall occur last.
CWE	CWE:561	Dead Code
	CWE:703	Improper Check or Handling of Exceptional Conditions
CERT-CPP	CERT-CPP:ERR51-CPP	Handle all exceptions
	CERT-CPP:ERR54-CPP	Catch handlers should order their parameter types from most derived to least derived
JSF++	JSF++:186	There shall be no unreachable code.

対応言語

C++ のみ利用可能です。 C は利用できません。

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="Unreachable Catch"

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 <exception>

class derived_excp : public std::exception {};
class more_derived_excp : public derived_excp {};

namespace lang_struct_uctch{

  void most_to_least(void){
    try {
    } catch ( more_derived_excp ) {
    } catch ( derived_excp ) {                 // ok: base class of more_derived_excp 
    } catch ( std::exception ) {               // ok: base class of derived_excp and more_derived_excp 
    }
  }

  void least_to_most(void){
    try {
    } catch ( std::exception ) {
    } catch ( derived_excp ) {      // 'Unreachable Catch' warning issued here
    } catch ( more_derived_excp ) { // 'Unreachable Catch' warning issued here
    }
  }

  void excp_ptr(void){
    try {
    } catch ( std::exception* ) {
    } catch ( derived_excp* ) {     // 'Unreachable Catch' warning issued here
    }
  }

   void excp_ref(void){
    try {
    } catch ( std::exception& ) {
    } catch ( derived_excp& ) {     // 'Unreachable Catch' warning issued here
    }
  }

  void void_ptr(void){
    try {
    } catch ( void*) {
    } catch ( std::exception* ) {   // 'Unreachable Catch' warning issued here
    }
  }

  void ellipsis(void){
    try {
    } catch (...) {
    } catch ( std::exception ) {    // 'Unreachable Catch' warning issued here
    }
  }

}

関連のある設定ファイルパラメータ

設定ファイルの以下のパラメータがこのワーニングクラスのチェックに影響します。