EXECVP系统调用是否支持IO重定向

Question

EXECVP系统调用是否支持IO重定向

这意味着这是给期望的输出

char *args[]={"cat","A.txt","B.txt",">","C.txt",NULL};
execvp(args[0],args);

我的意思是A.txt和B.txt中的数据会转到C.txt

如果没有，为什么？

UPD：我在评论中提出了两个疑问，请澄清

Answer 1

从技术上讲，这不是您问题的答案，已在 cmets 中回答。但是解释如何使用execvp进行重定向

当使用execvp 启动一个新程序时，它将继承当前的文件描述符。因此，如果您设置文件描述符 1（用于标准输出） 在调用execvp 之前重定向到“C.txt”，新程序将 写入“C.txt”：

// Open "C.txt" for writing, creating it if it doesn't exist, or
// clearing its content if it does exist.
// `mode` should be set as appropriate 
//
int fd = creat("C.txt", mode);
if (fd == -1)
{
   // Swap out error handling to suit your needs
   perror("open failed");
   exit(EXIT_FAILURE);
}

// We want new process to have "C.txt" on file descriptor 1
if (dup2(fd, 1) == -1)
{
   perror("dup failed");
   exit(EXIT_FAILURE);
}


// "C.txt" is now writable on file descriptor 1, so we don't need the
// old one. Actually, the old one could confuse the new executable.
close(fd);


// We can now execute new program. It will inherit current open 
// file descriptors and it will see "C.txt" on file descriptor 1
char *args[]={"cat","A.txt","B.txt",NULL};
execvp(args[0],args);

// If we reach this point, `execvp` failed.
perror("execvp failed");
exit(EXIT_FAILURE);