Event handlers?

I am using given code to handle mouse clicks. However, this is not working. I have gone through input.h to figure it out but I couldn't. bytes is 1 when it reaches if condition, but my code still doesnt allow execution to go inside if condition. What is that is being done wrong here:

const char *mfile = "/dev/input/mice";

int main()
O_NONBLOCK);
if(fd == -1)

printf("ERROR Opening associated device file: /dev/input/mice n");
return -1;


while(1)

bytes = read(fd, &data, sizeof(struct input_event));

if(bytes > 0)

if((data.code == BTN_LEFT) && (data.value == 0))
printf("Left pressed. n");
else if((data.code == BTN_RIGHT) && (data.value == 0))
printf("Right presseed. n");


close(fd);
return 0;



if (bytes > 0)

if (bytes == sizeof data)

bytes == 1

(data.code == BTN_LEFT) && (data.value == 0)

data

.code

.value

1 Answer
1

You will have to wait until read has read input the size of input_event structure before you process the data in it.

read

input_event

But the current code only checks if any bytes have been read. This check should be changed to check if the number of bytes read equals the input_event structure.

input_event

See the documentation of read:.

Return Value.

On success, the number of bytes read is returned (zero indicates end of file), and the file position is advanced by this number. It is not an error if this number is smaller than the number of bytes requested; this may happen for example because fewer bytes are actually available right now (maybe because we were close to end-of-file, or because we are reading from a pipe, or from a terminal), or because read() was interrupted by a signal. On error, -1 is returned, and errno is set appropriately. In this case it is left unspecified whether the file position (if any) changes.

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