C++ operatorに関して

VuMUL_bi_1wire_test& operator= (const VuMUL_bi_1wire_test&); ///< Copying not allowed
VuMUL_bi_1wire_test(const VuMUL_bi_1wire_test&); ///< Copying not allowed
と書かれている部分の意味が分かりません。
operatorに関して調べましたが、上の動作がどうなっているのかいまいち理解できませんでした。
一つ目はインスタンスのコピー操作を追加でしょうか。
二個目に関しては理解できません。
VuMUL_bi_1wire_testというClassのprivate部分に書かれています。

回答の程よろしくお願いいたします。

C++
1// Verilated -*- C++ -*-
2// DESCRIPTION: Verilator output: Primary design header
3//
4// This header should be included by all source files instantiating the design.
5// The class here is then constructed to instantiate the design.
6// See the Verilator manual for examples.
7
8#ifndef _VuMUL_bi_1wire_test_H_
9#define _VuMUL_bi_1wire_test_H_
10
11#include "verilated.h"
12
13class VuMUL_bi_1wire_test__Syms;
14class VerilatedVcd;
15
16//----------
17
18VL_MODULE(VuMUL_bi_1wire_test) {
19  public:
20    
21    // PORTS
22    // The application code writes and reads these signals to
23    // propagate new values into/out from the Verilated model.
24    VL_IN8(clk,0,0);
25    VL_IN8(rst_n,0,0);
26    VL_IN8(iA_trigger,0,0);
27    VL_IN8(iB_value,7,0);
28    VL_IN8(iA_value,7,0);
29    VL_IN8(loadA,0,0);
30    VL_IN8(loadB,0,0);
31    VL_OUT8(cntNum_iA,7,0);
32    VL_OUT8(cnt,7,0);
33    VL_OUT8(oC_sum,7,0);
34    
35    // LOCAL SIGNALS
36    // Internals; generally not touched by application code
37    VL_SIG8(uMUL_bi_1wire_test__DOT__iA,0,0);
38    VL_SIG8(uMUL_bi_1wire_test__DOT__iA_buf,7,0);
39    VL_SIG8(uMUL_bi_1wire_test__DOT__iA_sobolSeq,7,0);
40    VL_SIG8(uMUL_bi_1wire_test__DOT__U_SobolRNGDim1__DOT__vecIdx,2,0);
41    VL_SIG8(uMUL_bi_1wire_test__DOT__U_SobolRNGDim1__DOT__u_cntWithEn__DOT__cnt,7,0);
42    VL_SIG8(uMUL_bi_1wire_test__DOT__U_SobolRNGDim1__DOT__u_LSZ__DOT__inacc,7,0);
43    VL_SIG8(uMUL_bi_1wire_test__DOT__U_SobolRNGDim1__DOT__u_LSZ__DOT__outoh,7,0);
44    VL_SIG8(uMUL_bi_1wire_test__DOT__u_cntWithEn_A__DOT__cnt,7,0);
45    VL_SIG8(uMUL_bi_1wire_test__DOT__uMUL_bi_1wire__DOT__iB_buf,7,0);
46    VL_SIG8(uMUL_bi_1wire_test__DOT__uMUL_bi_1wire__DOT__counter_switch__DOT__cnt,7,0);
47    VL_SIG8(uMUL_bi_1wire_test__DOT__uMUL_bi_1wire__DOT__counter_switch__DOT__sum,7,0);
48    VL_SIG8(uMUL_bi_1wire_test__DOT__U_SobolRNGDim1__DOT__dirVec[8],7,0);
49    
50    // LOCAL VARIABLES
51    // Internals; generally not touched by application code
52    static VL_ST_SIG8(__Vtable1_uMUL_bi_1wire_test__DOT__U_SobolRNGDim1__DOT__vecIdx[256],2,0);
53    VL_SIG8(__Vtableidx1,7,0);
54    VL_SIG8(__Vclklast__TOP__clk,0,0);
55    VL_SIG8(__Vclklast__TOP__rst_n,0,0);
56    VL_SIG8(__Vchglast__TOP__uMUL_bi_1wire_test__DOT__U_SobolRNGDim1__DOT__u_LSZ__DOT__inacc,7,0);
57    VL_SIG(__Vm_traceActivity,31,0);
58    VL_SIG8(uMUL_bi_1wire_test__DOT__U_SobolRNGDim1__DOT____Vcellinp__u_SobolRNG__dirVec[8],7,0);
59    
60    // INTERNAL VARIABLES
61    // Internals; generally not touched by application code
62    VuMUL_bi_1wire_test__Syms* __VlSymsp;  // Symbol table
63    
64    // PARAMETERS
65    // Parameters marked /*verilator public*/ for use by application code
66    
67    // CONSTRUCTORS
68  private:
69    VuMUL_bi_1wire_test& operator= (const VuMUL_bi_1wire_test&);  ///< Copying not allowed
70    VuMUL_bi_1wire_test(const VuMUL_bi_1wire_test&);  ///< Copying not allowed
71  public:
72    /// Construct the model; called by application code
73    /// The special name  may be used to make a wrapper with a
74    /// single model invisible WRT DPI scope names.
75    VuMUL_bi_1wire_test(const char* name="TOP");
76    /// Destroy the model; called (often implicitly) by application code
77    ~VuMUL_bi_1wire_test();
78    /// Trace signals in the model; called by application code
79    void trace (VerilatedVcdC* tfp, int levels, int options=0);
80    
81    // API METHODS
82    /// Evaluate the model.  Application must call when inputs change.
83    void eval();
84    /// Simulation complete, run final blocks.  Application must call on completion.
85    void final();
86    
87    // INTERNAL METHODS
88  private:
89    static void _eval_initial_loop(VuMUL_bi_1wire_test__Syms* __restrict vlSymsp);
90  public:
91    void __Vconfigure(VuMUL_bi_1wire_test__Syms* symsp, bool first);
92  private:
93    static QData _change_request(VuMUL_bi_1wire_test__Syms* __restrict vlSymsp);
94  public:
95    static void _combo__TOP__3(VuMUL_bi_1wire_test__Syms* __restrict vlSymsp);
96  private:
97    void _ctor_var_reset();
98  public:
99    static void _eval(VuMUL_bi_1wire_test__Syms* __restrict vlSymsp);
100  private:
101#ifdef VL_DEBUG
102    void _eval_debug_assertions();
103#endif // VL_DEBUG
104  public:
105    static void _eval_initial(VuMUL_bi_1wire_test__Syms* __restrict vlSymsp);
106    static void _eval_settle(VuMUL_bi_1wire_test__Syms* __restrict vlSymsp);
107    static void _sequent__TOP__2(VuMUL_bi_1wire_test__Syms* __restrict vlSymsp);
108    static void _settle__TOP__1(VuMUL_bi_1wire_test__Syms* __restrict vlSymsp);
109    static void traceChgThis(VuMUL_bi_1wire_test__Syms* __restrict vlSymsp, VerilatedVcd* vcdp, uint32_t code);
110    static void traceChgThis__2(VuMUL_bi_1wire_test__Syms* __restrict vlSymsp, VerilatedVcd* vcdp, uint32_t code);
111    static void traceChgThis__3(VuMUL_bi_1wire_test__Syms* __restrict vlSymsp, VerilatedVcd* vcdp, uint32_t code);
112    static void traceChgThis__4(VuMUL_bi_1wire_test__Syms* __restrict vlSymsp, VerilatedVcd* vcdp, uint32_t code);
113    static void traceChgThis__5(VuMUL_bi_1wire_test__Syms* __restrict vlSymsp, VerilatedVcd* vcdp, uint32_t code);
114    static void traceChgThis__6(VuMUL_bi_1wire_test__Syms* __restrict vlSymsp, VerilatedVcd* vcdp, uint32_t code);
115    static void traceFullThis(VuMUL_bi_1wire_test__Syms* __restrict vlSymsp, VerilatedVcd* vcdp, uint32_t code);
116    static void traceFullThis__1(VuMUL_bi_1wire_test__Syms* __restrict vlSymsp, VerilatedVcd* vcdp, uint32_t code);
117    static void traceInitThis(VuMUL_bi_1wire_test__Syms* __restrict vlSymsp, VerilatedVcd* vcdp, uint32_t code);
118    static void traceInitThis__1(VuMUL_bi_1wire_test__Syms* __restrict vlSymsp, VerilatedVcd* vcdp, uint32_t code);
119    static void traceInit (VerilatedVcd* vcdp, void* userthis, uint32_t code);
120    static void traceFull (VerilatedVcd* vcdp, void* userthis, uint32_t code);
121    static void traceChg  (VerilatedVcd* vcdp, void* userthis, uint32_t code);
122} VL_ATTR_ALIGNED(128);
123
124#endif // guard

行動規範の内容に同意します

回答2件

ユーザー定義のコピーコンストラクタや代入演算子を定義しなければそれらは自動生成されます。なので、自動生成をさせないためにはユーザーがそれらを定義する必要がありました。

しかし、ユーザーが定義してしまえばコピーや代入が出来てしまいます。なので、コピーや代入をユーザー定義しつつそれらの操作が出来ないようにするために private として宣言するというイディオムが知られていて、質問の例もそれです。

C++11 以降では別の方法で自動生成を抑止できるのでこのイディオムはあまり使われなくなっているかもしれません。

投稿2021/04/30 16:32

SaitoAtsushi

総合スコア5684

abeno2365

2021/04/30 18:53

回答いただきありがとうございます。勉強になりました。ハードウェア出身の人たちが書いているので書き方が古いのかもしれません。

行動規範の内容に同意します

ベストアンサー

C++
1  private:
2    VuMUL_bi_1wire_test& operator= (const VuMUL_bi_1wire_test&);  ///< Copying not allowed
3    VuMUL_bi_1wire_test(const VuMUL_bi_1wire_test&);  ///< Copying not allowed