singleton.h，下面是原始碼

#include    <unistd.h>
#include    <pthread.h>
using namespace std;
class Lock  {
    private:
        pthread_mutex_t m_lock;
    public:
        Lock(pthread_mutex_t  cs) : m_lock(cs) {
            pthread_mutex_lock(&m_lock);
        }
        ~Lock() {
            pthread_mutex_unlock(&m_lock);
        }
};//鎖類，實現多執行緒環境下高效工作

class Singleton {
    private:
        Singleton() {};
        Singleton(const Singleton &);
        Singleton& operator = (const Singleton &);

    public:
        static Singleton *Instantialize();
        static Singleton *pInstance;
        static pthread_mutex_t  mutex;
};
#endif
 

singleton.cc檔案

<pre name="code" class="html">#include "singleton.h"
pthread_mutex_t  Singleton::mutex = PTHREAD_MUTEX_INITIALIZER;
Singleton* Singleton::pInstance = 0;

Singleton* Singleton::Instantialize()   {   
    if(pInstance == NULL)   {   
        //double check
        Lock lock(mutex);           //用lock實現執行緒安全，用資源管理類，實現異常安全
        //使用資源管理類，在丟擲異常的時候，資源管理類物件會被析構，析構總是發生的無論是因為異常丟擲還是語句塊結束。
        if(pInstance == NULL)   {   
            pInstance = new Singleton();
        }   
    }   
    return pInstance;
}
~                   
 

<pre name="code" class="html">#include    <iostream>
#include    <cassert>
#include    <unistd.h>
#include    <pthread.h>

#include    "singleton.h"

int main(int argc, char *argv[]) {
    Singleton *p = Singleton::Instantialize(); 
    Singleton *q = Singleton::Instantialize(); 
    assert(p != q); 
    return 0;
}
 

<pre name="code" class="html">#lizhiming
CC=gcc
CXX=g++
AR=ar
ARFLAGS=cru
CURRENT_DIR=$(shell echo `pwd`)
PARENT_DIRNAME=$(shell basename $(shell dirname $(CURRENT_DIR)))
SOURCE_DIR=$(CURRENT_DIR)/src
PREFIX=${CURRENT_DIR}
DEBUG :=
CFLAGS := $(DEBUG) -g -c -fPIC -Wshadow -Wcast-qual -Wcast-align  \
          -Wwrite-strings -Wsign-compare -Winvalid-pch -fms-extensions \
          -Wall \
          -I./include

CPPFLAGS=$(CFLAGS) -Woverloaded-virtual -Wsign-promo -fno-gnu-keywords

LDFLAGS=-L/usr/local/lib  \
        -lpthread\


DIRNAME=$(shell basename `pwd`)

SRCXXS := $(wildcard *.cc) \
          $(wildcard ./src/*.cc)

SRCS := $(SRCXXS)

CXXOBJS := $(patsubst %.cc, %.o, $(SRCXXS))
OBJS := ${CXXOBJS} \

DEPS := $(patsubst %.o, %.d, $(OBJS))

TARGET := lib$(PARENT_DIRNAME)_$(DIRNAME).so

ARFLAGS := -cvq

TARGET_A_LIB := lib$(PARENT_DIRNAME)_$(DIRNAME).a

all : $(TARGET) $(TARGET_A_LIB)
    
$(TARGET_A_LIB): $(OBJS)
    @ar $(ARFLAGS) [email protected] $^
    @ranlib [email protected] 

$(TARGET) : $(OBJS)
    $(CXX) $(OBJS) $(LDFLAGS) -o [email protected] -shared

-include $(DEPS)

%.o : %.cc
    $(CXX) $(CPPFLAGS) $< -o [email protected]



t:
    @echo "DIRNAME:" $(DIRNAME)
 @echo "PARENT_DIRNAME:" $(PARENT_DIRNAME)
    @echo "SRCS:" $(SRCS)
    @echo "OBJS:" $(OBJS)
    @echo "CFLAGS:" $(CFLAGS)
    @echo "CPPFLAGS:" $(CPPFLAGS)
    @echo "ARFLAGS:" $(ARFLAGS)


clean:
    rm -rf *.o *.d *.a $(OBJS) $(DEPS) $(TARGET)