用C写入文件后，while循环不会退出 [英] While loop doesn't exit after writing to file in C

问题描述

我正在从客户端向服务器发送文件.我从客户端获取输入，在这种情况下，它用于文件传输，完成后客户端应该重新提示输入新命令.这是我发送文件的方式:

I'm sending a file from the client to the server. I take an input from the client, and in this case its for file transfer and after completion the client is supposed to reprompt for a new command. This is how I send a file:

客户端(发送):

            size_t bytes_read = 0;
            ssize_t bytes_written = 0;
            
            
            while((bytes_read = fread(buf, 1, sizeof(buf), fp)) > 0){ 
            
                if ((bytes_written = write(sd, buf, bytes_read)) < 0){
                    printf("Error sending client file.\n");
                }
            
            }
            
            printf("bytes written: %ld\n", bytes_written);
            fclose(fp);
            }   

服务器(接收):

             while((bytes_read = read(sd, buf, sizeof(buf))) > 0){ 
                    
                printf("The contents: %s", buf);
                fwrite(buf, 1, bytes_read, fp);
                printf("Done writing\n");
                
                }
                printf("The server has received the requested document.\n");
                fclose(fp);

我遇到的问题是，打印语句printf("The server has received the requested document.\n");从未执行过，这是我在执行所有操作的IF语句关闭之前打印的最后一条语句.而且我无法从客户端输入新命令，因为我认为它陷入了while循环中.仅当我强制停止服务器程序时，才达到该打印行，然后程序退出.奇怪的是，在我强制停止它之后，我可以看到传输的文件实际上已经正确传输了.但是为什么不离开while循环呢?

The problem I'm having, is that the print statement printf("The server has received the requested document.\n"); is never executed which is the last statement I print before this IF statement carrying all the operations is closed. And I'm unable to enter new commands from the client because I assume its stuck in this while loop. Only when I force stop the server program, that print line is reached and then the program exits. The strange thing, is that after I force stop it I can see that the file I transferred has actually been transferred correctly. But why wont it leave this while loop?

推荐答案

(需要在注释上设置格式，所以是临时的CW答案)

(need formatting on a comment, so temporary CW answer)

仅当我强制停止服务器程序时，到达该打印行，然后程序退出.

Only when I force stop the server program, that print line is reached and then the program exits.

(他按^ Z将其推到背景中.)

(He presses ^Z shoving it into the background.)

问题不在发布的代码中.演示:在printf之后添加以下行:

The problem isn't in the posted code. Demonstration: add the following lines after printf:

fflush(stdout);
_exit(0);

Po，进程退出.

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