我有以下头文件MappingSingleton.h：
#include <vector>
#include <string>
#include <fstream>
#include <iostream>
#include<iterator>
#include <sstream>
#include <thread>
#include <mutex>
#include "SOPExpr.h"
class MappingSingleton {
private:
static MappingSingleton& mapping_singleton;
MappingSingleton();
public:
static unsigned int wireID;
static bool is_init;
std::vector<SOPExpr> m_hex_to_SOP_4;
std::vector<int> m_hex_to_line_number_4;
std::vector<SOPExpr> m_hex_to_SOP_3;
std::vector<int> m_hex_to_line_number_3;
std::vector<SOPExpr> m_hex_to_SOP_2;
std::vector<int> m_hex_to_line_number_2;
void loadLUTNHexToStringMapping(std::vector<SOPExpr>& m_hex_to_SOP, std::vector<int> &m_hex_to_line_number, short int LUT_size);
std::string getQTPrims(std::string& LUT_init_string);
static MappingSingleton getInstance();
private:
static void initSingleton();
static std::once_flag init_instance_flag;
int getExprIndex(std::string &key, short lut_size);
int wire_id;
};
以及MappingSingleton.cpp中的以下函数：
MappingSingleton MappingSingleton::getInstance() {
std::call_once(MappingSingleton::init_instance_flag,&MappingSingleton::initSingleton);
return mapping_singleton;
}
编译器给出以下错误：
/grid/cva/p4_02/hisham/gcc/ua/Framework/Roman/src/MappingSingleton.cpp:37: undefined reference to `MappingSingleton::initSingleton()'
/grid/cva/p4_02/hisham/gcc/ua/Framework/Roman/src/MappingSingleton.cpp:37: undefined reference to `MappingSingleton::init_instance_flag'
/grid/cva/p4_02/hisham/gcc/ua/Framework/Roman/src/MappingSingleton.cpp:38: undefined reference to `MappingSingleton::mapping_singleton'
我不明白为什么要在标题中清楚地定义这些变量/函数。我尝试阅读有关此错误的许多问题，但是没有提出的解决方案可以解决该错误。我的主要功能只是初始化Mapping Singleton。
MappingSingleton.cpp具有以下实现：
#include "MappingSingleton.h"
#include "HelperFunction.h"
#include <regex>
#include <cmath>
#include "WireNameReplacement.h"
bool MappingSingleton::is_init=false; //this is static in the header file
std::once_flag init_instance_flag;
MappingSingleton::MappingSingleton() {
wire_id=0; //used for avoiding duplicate wires.
//Only one mapping generator at a time. Singleton design pattern.
//Load mappings for the three LUTS
loadLUTNHexToStringMapping(m_hex_to_SOP_4,m_hex_to_line_number_4,4);
loadLUTNHexToStringMapping(m_hex_to_SOP_3,m_hex_to_line_number_3,3);
loadLUTNHexToStringMapping(m_hex_to_SOP_2,m_hex_to_line_number_2,2);
}
MappingSingleton MappingSingleton::getInstance() {
std::call_once(MappingSingleton::init_instance_flag,&MappingSingleton::initSingleton);
return mapping_singleton;
}
void MappingSingleton::loadLUTNHexToStringMapping(std::vector<SOPExpr>& m_hex_to_SOP, std::vector<int> &m_hex_to_line_number, short int LUT_size){
//Read in Vivado Hex key of each SOP for LUT 4
std::ifstream iFS("TextAndPythonFiles/LUT" +std::to_string(LUT_size)+"/lutListHex");
std::string temp_str;
m_hex_to_line_number.resize(pow(2,pow(2,LUT_size))); // 2^(2^4) for 4-LUT
int tempInt=0;
std::stringstream ss;
while (std::getline(iFS, temp_str, '\n')) {
m_hex_to_line_number[hexToInteger(temp_str)]=tempInt;
++tempInt;
}
//Read In the SOP Strings from a file. Reserve vector space first though to avoid reallocating vector.
//m_hex_to_SOP.resize(pow(2,pow(2,LUT_size)));
std::ifstream iFS2("TextAndPythonFiles/LUT"+std::to_string(LUT_size)+"/combinedTrimmedFinal.vg");
int tempInt2=0;
std::string current_SOP;
while (std::getline(iFS2, temp_str, '\n')) {
if(temp_str.empty()) //Blank line implies new module
{
if(!current_SOP.empty()) current_SOP.pop_back(); //Erase last new line. Not necessary.
SOPExpr expr(current_SOP);
m_hex_to_SOP.push_back(expr);
current_SOP.clear();
continue;
}
current_SOP.append(temp_str);
current_SOP.push_back('\n');
tempInt2++;
}
// createHexVec(line_num_to_SOP,m_hex_to_line_number); Reviewers please ignore
std::string test="Q_OAI222 g514(.A0 (n_5), .A1 (n_0), .B0 (n_4), .B1 (n_1), .C0 (n_2), .C1 (n_3), .Z (n_6));\n Q_INV g517(.A (i0), .Z (n_5));Q_INV g518(.A (i2), .Z (n_4));";
//std::cout<<findOutputWire(test);
}
std::string MappingSingleton::getQTPrims(std::string& vivado_LUT_string)
{
//find LUT Size
std::smatch match;
std::regex re("LUT([0-9])");
regex_search(vivado_LUT_string, match, re);
int LUT_size=std::stoi(match.str(1));
std::string key= extractHexKey(vivado_LUT_string);
int expr_index;
std::string qt_prims;
std::deque<std::string> d;
switch(LUT_size){
case 2: expr_index= getExprIndex(key,2);
qt_prims= m_hex_to_SOP_4[expr_index].getGateLevelNetList();
d=findWireNames(vivado_LUT_string);
qt_prims=replaceWireNames(d,vivado_LUT_string,qt_prims,2);
replaceAllInternalWires(qt_prims,wire_id);
return qt_prims;
case 3: expr_index= getExprIndex(key,3);
qt_prims= m_hex_to_SOP_4[expr_index].getGateLevelNetList();
d=findWireNames(vivado_LUT_string);
qt_prims= replaceWireNames(d,vivado_LUT_string,qt_prims,3);
replaceAllInternalWires(qt_prims,wire_id);
return qt_prims;
case 4: expr_index= getExprIndex(key,4);
qt_prims= m_hex_to_SOP_4[expr_index].getGateLevelNetList();
d=findWireNames(vivado_LUT_string);
qt_prims=replaceWireNames(d,vivado_LUT_string,qt_prims,4);
replaceAllInternalWires(qt_prims,wire_id);
return qt_prims;
default:
throw std::invalid_argument("Invalid LUT Init Val");
}
return "Invalid LUT Init Val";
}
int MappingSingleton::getExprIndex(std::string& key, short int LUT_size){
switch(LUT_size){
case 2: return m_hex_to_line_number_2[hexToInteger(key)];
case 3: return m_hex_to_line_number_3[hexToInteger(key)];
case 4: return m_hex_to_line_number_4[hexToInteger(key)];
default:
throw std::invalid_argument("Invalid LUT Init Val");
}
}
因此，首先，这是错误的：
std::once_flag init_instance_flag;
应该是这样的：
std::once_flag MappingSingleton::init_instance_flag; // maybe an init value here too
其次，即使您声明了MappingSingleton::mapping_singleton和MappingSingleton::initSingleton()，也没有针对它们的定义。最终它将看起来像这样：
// the actual definition of the variable
MappingSingleton& MappingSingleton::mapping_singleton;
// the actual implementation of the function
void MappingSingleton::initSingleton() {
// some implementation...
}
这是您的代码中缺少的，可能是导致您的错误的原因。