c++ - SIGINT上的C++程序内存泄漏

我有一个程序，用作套接字客户端，这是代码

#include <stdio.h>
#include <signal.h>
#include <iostream>
#include <stdlib.h>
#include <string.h>
#include <string>
#include <sys/socket.h>
#include <netdb.h>

using namespace std;

void signalHandler(const int signal) {
    cout << "SIGINT handled" << endl;
    exit(EXIT_SUCCESS);
}

void error(const char *msg) {
    perror(msg);
    exit(0);
}

const string readStr(int descriptor) {
    int n = 0;
    string cmd = "";

    char buffer[256];
    memset(buffer, 0, sizeof(buffer));

    while ((n = read(descriptor, buffer, 255)) != 0) {
        if (n < 0) {
            error("Error reading string");
        }

        // full string - just copy
        if (n == 255) {
            cmd += buffer;
            memset(buffer, 0, sizeof(buffer));
        }
        else {
            cmd += buffer;
            break;
        }
    }

    return cmd;
}

int main(int argc, char** argv) {
    signal(SIGINT, signalHandler);

    int fd, port = (argc >= 3 ? atoi(argv[2]) : 11212), n;
    fd = socket(AF_INET, SOCK_STREAM, 0);
    if (fd < 0) {
        error("ERROR opening socket");
    }

    struct hostent *server = (argc >= 2 ? gethostbyname(argv[1]) : gethostbyname("localhost"));
    if (server == NULL) {
        error("ERROR no such host");
    }

    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));

    addr.sin_family = AF_INET;
    bcopy(server->h_addr, &addr.sin_addr.s_addr, server->h_length);
    addr.sin_port = htons(port);

    if (connect(fd, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
        error("ERROR connecting");
    }

    string tmp;
    while (1) {
        cout << "Please enter the message: \n< " << flush;
        tmp = readStr(0);
        n = send(fd, tmp.c_str(), tmp.size(), 0);
        if (n < 0) {
            perror("ERROR writing to socket");
        }

        tmp = readStr(fd);
        cout << "> " << tmp << endl;
    }
    close(fd);

    return EXIT_SUCCESS;
}

当我发送SIGNINT以处理(CTRL + C)时，valgrind表示:

^ CSIGINT已处理
== 3798 ==
== 3798 ==堆摘要:
== 3798 ==在导出处使用:1块中39个字节
== 3798 ==总堆使用量:45个分配，44个释放，4,778个字节分配
== 3798 ==
== 3798 ==丢失记录1 of 1中可能会丢失1个块中的39个字节
== 3798 ==在0x402471C:运算符new(unsigned int)
(vg_replace_malloc.c:255)
== 3798 ==通过0x40DBB64:std::string::_ Rep::_ S_create(unsigned int，
unsigned int，std::allocator const＆)(在
/usr/lib/libstdc++.so.6.0.15)
== 3798 ==通过0x1BFF403:???
== 3798 ==
== 3798 ==泄漏摘要:
== 3798 ==肯定会丢失:0字节(0块)
== 3798 ==间接丢失:0个字节，共0个块
== 3798 ==可能丢失:1个块中39个字节
== 3798 ==仍可到达:0字节，共0块
== 3798 ==已抑制:0字节，0块
== 3798 ==
== 3798 ==有关检测到的和抑制的错误的计数，请重新运行:-v
== 3798 ==错误摘要:来自1个上下文的1个错误(禁止显示:9个中的20个)

如果程序正确退出，例如，如果用while(1)重新标记int i = 0; while(i++ <= 2)，则不会发生内存泄漏

那么有人可以帮我解决这个问题吗？

最佳答案

当您从信号处理程序中调用std::exit时，不会取消堆栈堆栈，并且不会破坏std::string中的tmp对象main这样的局部变量。

由于tmp不会在程序终止之前被销毁，因此它分配的内存永远不会释放，因此会泄漏。