最新做一个WIFI应用项目。如何检测WIFI USB设备是否插上了呢？特此共享。
第一种方法，采用读取文件的方式。在linux下，任何一种设备都可看成文件。通过分析相关文件信息，可得知WIFI设备是否存在；代码示例如下：
static void WIFI_Enum_Device(void)
{
char buff[1024];
FILE * fh;
/* Check if /proc/net/wireless is available */
fh = fopen(PROC_NET_WIRELESS, "r");
if(fh != NULL)
{
/* Success : use data from /proc/net/wireless */
/* Eat 2 lines of header */
fgets(buff, sizeof(buff), fh);
fgets(buff, sizeof(buff), fh);
/* Read each device line */
while(fgets(buff, sizeof(buff), fh))
{
char name[IFNAMSIZ + 1];
char *s;
/* Skip empty or almost empty lines. It seems that in some
* cases fgets return a line with only a newline. */
if((buff[0] == '\0') || (buff[1] == '\0'))
continue;
/* Extract interface name */
s = WIFI_Get_DeviceName(name, sizeof(name), buff);
if(!s)
{
/* Failed to parse, complain and continue */
#ifndef IW_RESTRIC_ENUM
fprintf(stderr, "Cannot parse " PROC_NET_DEV "\n");
#else
fprintf(stderr, "Cannot parse " PROC_NET_WIRELESS "\n");
#endif
}
else
/* Got it, save the name about this interface */
{//we always use the first detected device when doing first time detecting
if(s_DeviceCount == 0)
{
if(strcmp(s_Deviceinfo.DeviceName,name))
{
memset((char *)&s_Deviceinfo, 0, sizeof(DeviceInfo_t));
memcpy(s_Deviceinfo.DeviceName,name,IFNAMSIZ);
}
if(strlen(s_SavedDevice) == 0)//this is the first detected device when doing first time detecting, we save it
memcpy(s_SavedDevice,name,IFNAMSIZ);
}
else
{//there is more than one device, we should use the first detected
if(!strcmp(s_SavedDevice,name))
{
memset((char *)&s_Deviceinfo, 0, sizeof(DeviceInfo_t));
memcpy(s_Deviceinfo.DeviceName,name,IFNAMSIZ);
}
}
s_DeviceCount++;
}
}
fclose(fh);
}
}