c++代码实现linux命令pmap

以下是使用 C++ 实现 `pmap` 命令的示例代码：

#include <iostream>
#include <fstream>
#include <string>
#include <sstream>
#include <iomanip>

using namespace std;

string to_hex(unsigned long long value) {
    stringstream stream;
    stream << "0x" << setfill('0') << setw(sizeof(void*)*2) << hex << value;
    return stream.str();
}

int main(int argc, char** argv) {
    if (argc != 2) {
        cout << "Usage: " << argv[0] << " <process-id>" << endl;
        return 1;
    }

    ifstream ifs("/proc/" + string(argv[1]) + "/maps");
    if (!ifs) {
        cout << "Failed to open /proc/" << argv[1] << "/maps" << endl;
        return 2;
    }

    string line;
    while (getline(ifs, line)) {
        unsigned long long start, end;
        string perms, offset, device, inode, pathname;
        istringstream iss(line);
        iss >> hex >> start;
        iss.ignore(1, '-');
        iss >> hex >> end;
        iss >> perms >> offset >> device >> inode >> pathname;
        cout << to_hex(start) << "-" << to_hex(end) << " " << perms << " " << offset << " " << device << " " << inode;
        if (!pathname.empty()) {
            cout << " " << pathname;
        }
        cout << endl;
    }

    return 0;
}

该程序会读取指定进程的 `/proc/<pid>/maps` 文件，解析其中的每一行内容，并将其输出到标准输出。输出的格式与 `pmap` 命令相同。