C++ IPC使用多管道和分叉进程运行Python程序
我的作业遇到了一个难题。我尝试执行3个并发进程(C++),其中2个是Python程序,其中一个是C++程序。p>C++ IPC使用多管道和分叉进程运行Python程序,c++,pipe,fork,ipc,dup2,C++,Pipe,Fork,Ipc,Dup2,我的作业遇到了一个难题。我尝试执行3个并发进程(C++),其中2个是Python程序,其中一个是C++程序。p> 我的C++程序(SAMP.CPP): 我的Python程序2(sample2.py): 这是我的驱动程序C++程序,它的处理过程是: #include <unistd.h> #include <stdio.h> #include <string.h> #include <string> #include <stdlib.h&g
我的C++程序(SAMP.CPP):
我的Python程序2(sample2.py):这是我的驱动程序C++程序,它的处理过程是:
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <string>
#include <stdlib.h>
#include <iostream>
#include <vector>
#include <signal.h>
using namespace std;
int main()
{
vector<pid_t> kids;
int fd[2];
if (pipe(fd) < 0)
{
cout << "Error";
return 1;
}
int fd2[2];
if (pipe(fd2) < 0)
{
cout << "Error";
return 1;
}
pid_t pid;
pid = fork();
if (pid == 0)
{
dup2(fd[1], STDOUT_FILENO);
close(fd[1]);
close(fd[0]);
while (true)
{
execvp("./sample", NULL);
}
}
else
{
kids.push_back(pid);
pid = fork();
if (pid == 0)
{
dup2(fd[0], STDIN_FILENO);
close(fd[0]);
close(fd[1]);
dup2(fd2[1], STDOUT_FILENO);
close(fd2[1]);
close(fd2[0]);
char * python = "/usr/bin/python";
char * pythonProgram = "./sample.py";
char * pythonArgs[] = {python, pythonProgram, NULL, NULL};
execvp(python, pythonArgs);
}
else
{
kids.push_back(pid);
pid = fork();
if (pid == 0)
{
dup2(fd2[0], STDIN_FILENO);
close(fd2[0]);
close(fd2[1]);
char * python = "/usr/bin/python";
char * pythonProgram = "./sample2.py";
char * pythonArgs[] = {python, pythonProgram, NULL, NULL};
execvp(python, pythonArgs);
}
else
{
kids.push_back(pid);
}
}
}
close(fd[0]);
close(fd[1]);
close(fd2[0]);
close(fd2[1]);
for (pid_t k : kids)
{
int status;
//kill (k, SIGTERM);
waitpid(k, &status, 0);
}
}
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使用名称空间std;
int main()
{
媒介儿童;
int-fd[2];
如果(管道(fd)<0)
{
cout除非您期望execvp失败,否则围绕./sample开头的while循环是毫无意义的。对execvp*的成功调用将永远不会返回。对execvp*的实际调用也是错误的:
execvp("./sample", NULL);
第二个参数应该是char*const[]
您应该为execvp:s添加错误处理(如带有std::exit(1)
)的行)。否则,如果execvp失败,您将在程序的主流程中运行子进程
python程序需要在没有缓冲的情况下运行,否则消息将需要很长时间才能显示。您还应该检查readline是否成功
sample.py
import sys
while True:
line = sys.stdin.readline().strip()
if not line: break
print "Python says: " + str(line)
样本2.py
import sys
while True:
line = sys.stdin.readline().strip()
if not line: break
print "Python 2 says: " + str(line)
driver.cpp
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <string>
#include <stdlib.h>
#include <iostream>
#include <vector>
#include <signal.h>
#include <sys/types.h>
#include <sys/wait.h>
using namespace std;
int main()
{
vector<pid_t> kids;
int fd[2];
if (pipe(fd)==-1)
{
clog << "Error\n";
return 1;
}
int fd2[2];
if (pipe(fd2)==-1)
{
clog << "Error\n";
return 1;
}
pid_t pid;
pid = fork();
if (pid == 0)
{
dup2(fd[1], STDOUT_FILENO);
close(fd[1]);
close(fd[0]);
char* const args[] = { NULL };
execvp("./sample", args);
std::clog << "sample failed\n";
std::exit(1);
}
else
{
kids.push_back(pid);
pid = fork();
if (pid == 0)
{
dup2(fd[0], STDIN_FILENO);
close(fd[0]);
close(fd[1]);
dup2(fd2[1], STDOUT_FILENO);
close(fd2[1]);
close(fd2[0]);
char const* python = "/usr/bin/python";
char const* pythonProgram = "./sample.py";
char const* pythonArgs[] = {python, "-u", pythonProgram, NULL};
execvp(python, const_cast<char* const*>(pythonArgs));
std::clog << "sample.py failed\n";
std::exit(1);
}
else
{
kids.push_back(pid);
pid = fork();
if (pid == 0)
{
dup2(fd2[0], STDIN_FILENO);
close(fd2[0]);
close(fd2[1]);
char const* python = "/usr/bin/python";
char const* pythonProgram = "./sample2.py";
char const* pythonArgs[] = {python, "-u", pythonProgram, NULL};
execvp(python, const_cast<char* const*>(pythonArgs));
std::clog << "sample2.py failed\n";
std::exit(1);
}
else
{
kids.push_back(pid);
}
}
}
close(fd[0]);
close(fd[1]);
close(fd2[0]);
close(fd2[1]);
for (pid_t k : kids)
{
int status;
//kill (k, SIGTERM);
waitpid(k, &status, 0);
}
}
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使用名称空间std;
int main()
{
媒介儿童;
int-fd[2];
如果(管道(fd)=-1)
{
阻塞我不知道你说的不从管道读取是什么意思。我只是想通过复制stdin/stdout将所有输出从sample.cpp重定向到sample.py再重定向到sample2.py。你说的从管道读取是什么意思?我也不太明白你说的输入字符串是什么意思?你是说python程序需要参数吗?如果是,唯一的目的是python程序的ose是从stdin读取数据并生成到stdout(而不接受任何参数)。
import sys
while True:
line = sys.stdin.readline().strip()
if not line: break
print "Python says: " + str(line)
import sys
while True:
line = sys.stdin.readline().strip()
if not line: break
print "Python 2 says: " + str(line)
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <string>
#include <stdlib.h>
#include <iostream>
#include <vector>
#include <signal.h>
#include <sys/types.h>
#include <sys/wait.h>
using namespace std;
int main()
{
vector<pid_t> kids;
int fd[2];
if (pipe(fd)==-1)
{
clog << "Error\n";
return 1;
}
int fd2[2];
if (pipe(fd2)==-1)
{
clog << "Error\n";
return 1;
}
pid_t pid;
pid = fork();
if (pid == 0)
{
dup2(fd[1], STDOUT_FILENO);
close(fd[1]);
close(fd[0]);
char* const args[] = { NULL };
execvp("./sample", args);
std::clog << "sample failed\n";
std::exit(1);
}
else
{
kids.push_back(pid);
pid = fork();
if (pid == 0)
{
dup2(fd[0], STDIN_FILENO);
close(fd[0]);
close(fd[1]);
dup2(fd2[1], STDOUT_FILENO);
close(fd2[1]);
close(fd2[0]);
char const* python = "/usr/bin/python";
char const* pythonProgram = "./sample.py";
char const* pythonArgs[] = {python, "-u", pythonProgram, NULL};
execvp(python, const_cast<char* const*>(pythonArgs));
std::clog << "sample.py failed\n";
std::exit(1);
}
else
{
kids.push_back(pid);
pid = fork();
if (pid == 0)
{
dup2(fd2[0], STDIN_FILENO);
close(fd2[0]);
close(fd2[1]);
char const* python = "/usr/bin/python";
char const* pythonProgram = "./sample2.py";
char const* pythonArgs[] = {python, "-u", pythonProgram, NULL};
execvp(python, const_cast<char* const*>(pythonArgs));
std::clog << "sample2.py failed\n";
std::exit(1);
}
else
{
kids.push_back(pid);
}
}
}
close(fd[0]);
close(fd[1]);
close(fd2[0]);
close(fd2[1]);
for (pid_t k : kids)
{
int status;
//kill (k, SIGTERM);
waitpid(k, &status, 0);
}
}