看了几天asio文档，总算可以写点小程序了。有些细节还是没弄明白，同步IO好像还不能设超时？服务器端采用异步IO，客户端则采用同步IO。传送文件，不得不注意到 C/C++ 2G文件限制，好像没通用的解决方法。

先定义下头文件，统一下asio和boost_asio。

#ifndef _FILE_INFO_H_
#define _FILE_INFO_H_

#if USE_ASIO_ALONE
#include
#else
#include
namespace asio {
using namespace boost::asio;
using boost::system::error_code;
}
#endif

struct File_info {
typedef unsigned long long Size_type;
Size_type filesize;
size_t filename_size;
File_info() : filesize(0), filename_size(0) {}
};

#endif

client_sender

//www.cnblogs.com/flyinghearts

#include
#include
#include
#include
#include "file_info.h"

void sender(asio::io_service& io, const char* ip_address, unsigned port, const char* filename)
{
typedef asio::ip::tcp TCP;

FILE *fp = fopen(filename, "rb");
if (fp == NULL) {
std::cerr << "cannot open file ";
return;
}

//使用智能指针，防止程序出现异常时，fclose未被调用。
boost::shared_ptr file_ptr(fp, fclose);

clock_t cost_time = clock();

const size_t k_buffer_size = 32 * 1024;
char buffer[k_buffer_size];
File_info file_info;

int filename_size = strlen(filename) + 1;
size_t file_info_size = sizeof(file_info);
size_t total_size = file_info_size + filename_size;
if (total_size > k_buffer_size) {
std::cerr << "File name is too long";
return;
}
file_info.filename_size = filename_size;

fseek(fp, 0, SEEK_END);
file_info.filesize = ftell(fp);
rewind(fp);

memcpy(buffer, &file_info, file_info_size);
memcpy(buffer + file_info_size, filename, filename_size);

TCP::socket socket(io);
socket.connect(TCP::endpoint(asio::ip::address_v4::from_string(ip_address), port));

std::cout << "Sending file : " << filename << " ";
size_t len = total_size;
unsigned long long total_bytes_read = 0;
while (true) {
socket.send(asio::buffer(buffer, len), 0);
if (feof(fp)) break;
len = fread(buffer, 1, k_buffer_size, fp);
total_bytes_read += len;
}

cost_time = clock() - cost_time;
if (cost_time == 0) cost_time = 1;
double speed = total_bytes_read * (CLOCKS_PER_SEC / 1024.0 / 1024.0) / cost_time;
std::cout << "cost time: " << cost_time / (double) CLOCKS_PER_SEC << " s "
<< " transferred_bytes: " << total_bytes_read << " bytes "
<< "speed: " << speed << " MB/s ";
}

int main(int args, char* argc[])
{
if (args < 3) {
std::cerr << "Usage: " << argc[0] << " ip_address filename1 filename2 ";
return 1;
}

asio::io_service io;
for (int i = 2; i < args; ++i) {
try { sender(io, argc[1], 1345, argc[i]); }
catch (std::exception& err) {
std::cerr << err.what() << " ";
}
}
}

server_receiver

//www.cnblogs.com/flyinghearts
#include
#include
#include
#include
#include

#include "file_info.h"