我有两个这样的流的来源：
bp::ipstream StdOut;
bp::opstream StdIn;
bp::child MyProcess = bp::child(processPath, bp::std_out > StdOut, bp::std_in < StdIn);
// Doing some stuff with StdOut and StdIn
我想知道是否有办法手动写入这个 StdOut 并从 StdIn 读取以进行单元测试？非常感谢！
问问题
343 次
1 回答
2
您可以将它们作为普通流写入：
#include <boost/process.hpp>
#include <iostream>
namespace bp = boost::process;
int main() {
bp::ipstream StdOut;
bp::opstream StdIn;
bp::child MyProcess = bp::child("/usr/bin/rev", bp::std_out > StdOut, bp::std_in < StdIn);
for (int i = 0; i<100; ++i) {
StdIn << "Sure no problem, " << i << std::endl;
}
StdIn.flush();
StdIn.pipe().close();
std::string il;
while (getline(StdOut, il)) {
std::cout << il << std::endl;
}
std::cout << "Bye\n";
}
印刷
0 ,melborp on eruS
1 ,melborp on eruS
2 ,melborp on eruS
...
99 ,melborp on eruS
Bye
异步版本
请注意，就像文档警告的那样，如果您的进程需要异步 IO，您最终可能会陷入死锁（例如，在子进程等待输入时等待输出）。
为此，请使用 Asio 的异步操作：
#include <boost/process.hpp>
#include <boost/asio.hpp>
#include <boost/process/async.hpp>
#include <iostream>
namespace ba = boost::asio;
namespace bp = boost::process;
int main() {
ba::io_context io;
bp::async_pipe ip(io), op(io);
//bp::async_pipe StdIn(io);
bp::child MyProcess = bp::child("/usr/bin/tac", bp::std_out > op, bp::std_in < ip, io);
std::function<void()> send_loop, recv_loop;
ba::streambuf sb;
send_loop = [&, i=0]() mutable {
if (++i<100) {
std::ostream(&sb) << "Sure no problem, " << i << std::endl;
ba::async_write(ip, sb, [&send_loop](auto ec, auto /*tx*/) {
//std::cout << "Sent " << tx << " bytes (" << ec.message() << ")\n";
if (!ec) send_loop();
});
} else ip.close();
};
ba::streambuf rb;
recv_loop = [&]() {
ba::async_read_until(op, rb, "\n", [&](auto ec, auto /*tx*/) {
//std::cout << "Received " << tx << " bytes (" << ec.message() << ")\n";
std::cout << &rb << std::flush;
if (!ec) recv_loop();
});
};
io.post(send_loop);
io.post(recv_loop);
io.run();
std::cout << "Bye\n";
}
打印预期：
Sure no problem, 99
Sure no problem, 98
Sure no problem, 97
Sure no problem, 96
Sure no problem, 95
Sure no problem, 94
Sure no problem, 93
Sure no problem, 92
Sure no problem, 91
Sure no problem, 90
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Sure no problem, 1
Sure no problem, 1
于 2020-04-22T18:28:35.927 回答