将printf和cout重定向到套接字

Question

I am thinking if it is possible to redirect printf or cout to a socket easily?

I am currently programming in Windows VC++ btw...

Answer 1

No, but you can use the sprintf family of functions:

// Make sure this buffer is big enough; if the maximum size isn't known, use
// _vscprintf or a dynamically allocated buffer if you want to avoid truncation
char buffer[2048];
_snprintf_s(buffer, sizeof(buffer), _TRUNCATE, "format %s etc.", args...);
send(mySocket, buffer, strlen(buffer)+1, 0);  // +1 for NUL terminator

Note that _snprintf_s is a Microsoft runtime-only function, so if you're writing portable code, use snprintf instead on other platforms.

In C++, you can also use a std::ostringstream for similar results:

std::ostringstream buffer;
buffer << "test: " << myvar << somethingelse << etc;
send(mySocket, buffer.str().c_str(), buffer.str().size() + 1, 0);
                                                     // +1 for NUL terminator

Answer 2

Not trivially. In WinSock (MS Windows) world sockets are not the same as file descriptors.

Answer 3

Linux has dprintf() which allows you to write to a socket file descriptor.

int dprintf(int fd, const char *format, ...);

http://linux.about.com/library/cmd/blcmdl3_dprintf.htm