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我正在從一個USB控制桿獲取軸值並通過TCP發送它的程序。我所做的是首先讓TCP程序工作，這樣我就可以發送按預期工作的消息。然後我編寫了另一個程序，從操縱桿獲取數值並將它們打印到屏幕上，該屏幕也按預期工作。保持垃圾值
我最近試圖將這兩個單獨的程序合併爲一個，所以我有一個server程序和一個client程序。這就是我的問題開始的地方，在編譯期間我沒有遇到任何錯誤。看來該程序不再從遊戲杆獲取值並將它們存儲在變量axis[0]中。
現在我的過程是在連接操縱桿的電腦上啓動server.c文件。然後，我將在應該接收值的計算機上啓動client.c文件。我有幾個printf聲明，告訴我腳本到目前爲止的位置。當我執行server.c腳本時，它告訴我檢測到操縱桿並且有6個軸和12個按鈕。然後它將等待一個循環，直到嘗試連接客戶端。
一旦client.c程序被執行，它將打印出The value is -1093458243。在它下面將打印出Incoming connection from 192.168.254.15 - sending welcome.然後客戶端程序退出，這就是發生的一切。
說The value is:應該是一個介於-32768和32767之間的行。所以它從某個地方得到一個垃圾值。我迷路了，一直試圖排除一整天的麻煩，但沒有運氣。我已經包含了幾個代碼示例，工作TCP server和client腳本以及工作joystick腳本與我嘗試將兩者結合使用的代碼。如果有人可以看看我的代碼，看看他們是否發現錯誤或給我一些指針，我將不勝感激。提前致謝！
這裏是server.c結合的編碼：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
//joysick libraries
#include <sys/ioctl.h>
#include <stdio.h>
#include <fcntl.h>
#include <linux/joystick.h>
//Joysick device
#define JOY_DEV "/dev/input/js0"
//TCP Port number
#define PORTNUM 2343
int main(int argc, char *argv[])
{
//TCP connect
struct sockaddr_in dest; /* socket info about the machine connecting to us */
struct sockaddr_in serv; /* socket info about our server */
int mysocket; /* socket used to listen for incoming connections */
socklen_t socksize = sizeof(struct sockaddr_in);
memset(&serv, 0, sizeof(serv)); /* zero the struct before filling the fields */
serv.sin_family = AF_INET; /* set the type of connection to TCP/IP */
serv.sin_addr.s_addr = htonl(INADDR_ANY); /* set our address to any interface */
serv.sin_port = htons(PORTNUM); /* set the server port number */
mysocket = socket(AF_INET, SOCK_STREAM, 0);
/* bind serv information to mysocket */
bind(mysocket, (struct sockaddr *)&serv, sizeof(struct sockaddr));
/* start listening, allowing a queue of up to 1 pending connection */
listen(mysocket, 1);
int consocket = accept(mysocket, (struct sockaddr *)&dest, &socksize);
//TCP variable
char msg1[10];
//Joystick variables
int xAxis;
int yAxis;
int xSpeed;
int ySpeed;
//Joystick initialize
int joy_fd, *axis=NULL, num_of_axis=0, num_of_buttons=0, x;
char *button=NULL, name_of_joystick[80];
struct js_event js;
if((joy_fd = open(JOY_DEV , O_RDONLY)) == -1)
{
printf("Couldn't open joystick\n");
return -1;
}
//Get number of axes, buttons and name of joystick. Print results to screen
ioctl(joy_fd, JSIOCGAXES, &num_of_axis);
ioctl(joy_fd, JSIOCGBUTTONS, &num_of_buttons);
ioctl(joy_fd, JSIOCGNAME(80), &name_of_joystick);
axis = (int *) calloc(num_of_axis, sizeof(int));
button = (char *) calloc(num_of_buttons, sizeof(char));
printf("Joystick detected: %s\n\t%d axis\n\t%d buttons\n\n"
, name_of_joystick
, num_of_axis
, num_of_buttons);
//Use non blocking mode for joystick
fcntl(joy_fd, F_SETFL, O_NONBLOCK); /* use non-blocking mode */
while(1) {
//Test to read joystick state
/* read the joystick state */
read(joy_fd, &js, sizeof(struct js_event));
/* see what to do with the event */
switch (js.type & ~JS_EVENT_INIT)
{
case JS_EVENT_AXIS:
axis [ js.number ] = js.value;
break;
case JS_EVENT_BUTTON:
button [ js.number ] = js.value;
break;
}
//Give msg1 variable the value of axis[0]
sprintf(msg1, "%d", axis[0]);
//char msg1 = axis[0];
//TCP send
while(consocket)
{
printf("Value is: %6d\n", axis[0]);
printf("Incoming connection from %s - sending welcome\n", inet_ntoa(dest.sin_addr));
send(consocket, msg1, strlen(msg1), 0);
consocket = accept(mysocket, (struct sockaddr *)&dest, &socksize);
}
close(consocket);
close(mysocket);
return EXIT_SUCCESS;
//Print joystick state to screen
printf("Value is: %d", axis[0]);
//printf(" \r");
//fflush(stdout);
}
//Joystick close
close(joy_fd); /* too bad we never get here */
return 0;
//TCP message
//printf("Please enter info\n");
//fgets(msg1, 20, stdin);
}
這裏是老工作server.c文件：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#define PORTNUM 2343
int main(int argc, char *argv[])
{
char msg1[] = "Hello World !\n";
struct sockaddr_in dest; /* socket info about the machine connecting to us */
struct sockaddr_in serv; /* socket info about our server */
int mysocket; /* socket used to listen for incoming connections */
socklen_t socksize = sizeof(struct sockaddr_in);
memset(&serv, 0, sizeof(serv)); /* zero the struct before filling the fields */
serv.sin_family = AF_INET; /* set the type of connection to TCP/IP */
serv.sin_addr.s_addr = htonl(INADDR_ANY); /* set our address to any interface */
serv.sin_port = htons(PORTNUM); /* set the server port number */
mysocket = socket(AF_INET, SOCK_STREAM, 0);
/* bind serv information to mysocket */
bind(mysocket, (struct sockaddr *)&serv, sizeof(struct sockaddr));
/* start listening, allowing a queue of up to 1 pending connection */
listen(mysocket, 1);
int consocket = accept(mysocket, (struct sockaddr *)&dest, &socksize);
while(consocket)
{
printf("Incoming connection from %s - sending welcome\n", inet_ntoa(dest.sin_addr));
send(consocket, msg1, strlen(msg1), 0);
consocket = accept(mysocket, (struct sockaddr *)&dest, &socksize);
}
close(consocket);
close(mysocket);
return EXIT_SUCCESS;
}
這裏是client.c文件：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#define MAXRCVLEN 500
#define PORTNUM 2343
int main(int argc, char *argv[])
{
char buffer[MAXRCVLEN + 1]; /* +1 so we can add null terminator */
int len, mysocket;
struct sockaddr_in dest;
mysocket = socket(AF_INET, SOCK_STREAM, 0);
memset(&dest, 0, sizeof(dest)); /* zero the struct */
dest.sin_family = AF_INET;
dest.sin_addr.s_addr = inet_addr("192.168.254.16"); /* set destination IP number */
dest.sin_port = htons(PORTNUM); /* set destination port number */
connect(mysocket, (struct sockaddr *)&dest, sizeof(struct sockaddr));
len = recv(mysocket, buffer, MAXRCVLEN, 0);
/* We have to null terminate the received data ourselves */
buffer[len] = '\0';
printf("Received %s (%d bytes).\n", buffer, len);
close(mysocket);
return EXIT_SUCCESS;
}
這是joystick獲取的文件S中的值，並將其打印在屏幕上：
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <linux/joystick.h>
#include <wiringPi.h>
#define JOY_DEV "/dev/input/js0"
int main()
{
int xAxis;
int yAxis;
int xSpeed;
int ySpeed;
FILE *fp;
fp = fopen("/dev/servoblaster","w");
if (fp == NULL) {
printf("Error opening file");
exit(0);
}
int joy_fd, *axis=NULL, num_of_axis=0, num_of_buttons=0, x;
char *button=NULL, name_of_joystick[80];
struct js_event js;
if((joy_fd = open(JOY_DEV , O_RDONLY)) == -1)
{
printf("Couldn't open joystick\n");
return -1;
}
ioctl(joy_fd, JSIOCGAXES, &num_of_axis);
ioctl(joy_fd, JSIOCGBUTTONS, &num_of_buttons);
ioctl(joy_fd, JSIOCGNAME(80), &name_of_joystick);
axis = (int *) calloc(num_of_axis, sizeof(int));
button = (char *) calloc(num_of_buttons, sizeof(char));
printf("Joystick detected: %s\n\t%d axis\n\t%d buttons\n\n"
, name_of_joystick
, num_of_axis
, num_of_buttons);
fcntl(joy_fd, F_SETFL, O_NONBLOCK); /* use non-blocking mode */
while(1) /* infinite loop */
{
/* read the joystick state */
read(joy_fd, &js, sizeof(struct js_event));
/* see what to do with the event */
switch (js.type & ~JS_EVENT_INIT)
{
case JS_EVENT_AXIS:
axis [ js.number ] = js.value;
break;
case JS_EVENT_BUTTON:
button [ js.number ] = js.value;
break;
}
/* print the results */
//printf("X: %6d Y: %6d ", axis[0], axis[1]);
int xAxis = axis[0]/327;
int yAxis = axis[1]/327;
int ySpeed = 150-0.3*yAxis;
int xSpeed = 150-0.3*xAxis;
printf("X is equal to: %d Y is equal to: %d Y speed is: %d ", xAxis, yAxis, ySpeed);
fprintf(fp, "2=%d\n", ySpeed);
fprintf(fp, "1=%d\n", xSpeed);
printf(" \r");
fflush(stdout);
}
close(joy_fd); /* too bad we never get here */
return 0;
}