捕獲C++命令行的輸出

How to execute a command and get return code stdout and stderr of command in C++

目的：調用外部exe時，捕獲其返回值及屏幕輸出。

環境：Windows 10

#include <cstdio>
#include <iostream>
#include <memory>
#include <stdexcept>
#include <string>
#include <array>
#include <utility>
using namespace std;

pair<string, int> exec(const char* cmd) {
    array<char, 128> buffer;
    string result;
    int return_code = -1;
    auto pclose_wrapper = [&return_code](FILE* cmd) { return_code = _pclose(cmd); };
    { // scope is important, have to make sure the ptr goes out of scope first
        const unique_ptr<FILE, decltype(pclose_wrapper)> pipe(_popen(cmd, "r"), pclose_wrapper);
        if (pipe) {
            while (fgets(buffer.data(), buffer.size(), pipe.get()) != nullptr) {
                result += buffer.data();
            }
        }
    }
    return make_pair(result, return_code);
}

若要獲取stderr，在cmd參數中添加2>&1。如：

auto info = exec("test.exe 2>&1");

捕獲到的stderr：

How do I execute a command and get the output of the command within C++ using POSIX?

僅獲取exe屏幕輸出 C++ 11

#include <cstdio>
#include <iostream>
#include <memory>
#include <stdexcept>
#include <string>
#include <array>
std::string exec(const char* cmd) {
    std::array<char, 128> buffer;
    std::string result;
    std::unique_ptr<FILE, decltype(&_pclose)> pipe(_popen(cmd, "r"), _pclose);
    if (!pipe) {
        throw std::runtime_error("popen() failed!");
    }
    while (fgets(buffer.data(), buffer.size(), pipe.get()) != nullptr) {
        result += buffer.data();
    }
    return result;
}

C++ 11以前

#include <iostream>
#include <stdexcept>
#include <stdio.h>
#include <string>

std::string exec(const char* cmd) {
    char buffer[128];
    std::string result = "";
    FILE* pipe = _popen(cmd, "r");
    if (!pipe) throw std::runtime_error("popen() failed!");
    try {
        while (fgets(buffer, sizeof buffer, pipe) != NULL) {
            result += buffer;
        }
    }
    catch (...) {
        _pclose(pipe);
        throw;
    }
    _pclose(pipe);
    return result;
}