samples/uhid/uhid-example.c

File Facts

System

Linux kernel

Corpus path

samples/uhid/uhid-example.c

Extension

.c

Size

11301 bytes

Lines

466

Domain

Support Tooling And Documentation

Bucket

samples

Inferred role

Support Tooling And Documentation: implementation source

Status

source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

• Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• errno.h
• fcntl.h
• poll.h
• stdbool.h
• stdio.h
• stdlib.h
• string.h
• termios.h
• unistd.h
• linux/uhid.h

Detected Declarations

• function uhid_write
• function create
• function destroy
• function handle_output
• function event
• function send_event
• function keyboard
• function main

Annotated Snippet

switch (buf[i]) {
		case '1':
			btn1_down = !btn1_down;
			ret = send_event(fd);
			if (ret)
				return ret;
			break;
		case '2':
			btn2_down = !btn2_down;
			ret = send_event(fd);
			if (ret)
				return ret;
			break;
		case '3':
			btn3_down = !btn3_down;
			ret = send_event(fd);
			if (ret)
				return ret;
			break;
		case 'a':
			abs_hor = -20;
			ret = send_event(fd);
			abs_hor = 0;
			if (ret)
				return ret;
			break;
		case 'd':
			abs_hor = 20;
			ret = send_event(fd);
			abs_hor = 0;
			if (ret)
				return ret;
			break;
		case 'w':
			abs_ver = -20;
			ret = send_event(fd);
			abs_ver = 0;
			if (ret)
				return ret;
			break;
		case 's':
			abs_ver = 20;
			ret = send_event(fd);
			abs_ver = 0;
			if (ret)
				return ret;
			break;
		case 'r':
			wheel = 1;
			ret = send_event(fd);
			wheel = 0;
			if (ret)
				return ret;
			break;
		case 'f':
			wheel = -1;
			ret = send_event(fd);
			wheel = 0;
			if (ret)
				return ret;
			break;
		case 'q':
			return -ECANCELED;
		default:
			fprintf(stderr, "Invalid input: %c\n", buf[i]);
		}
	}

	return 0;
}

int main(int argc, char **argv)
{
	int fd;
	const char *path = "/dev/uhid";
	struct pollfd pfds[2];
	int ret;
	struct termios state;

	ret = tcgetattr(STDIN_FILENO, &state);
	if (ret) {
		fprintf(stderr, "Cannot get tty state\n");
	} else {
		state.c_lflag &= ~ICANON;
		state.c_cc[VMIN] = 1;
		ret = tcsetattr(STDIN_FILENO, TCSANOW, &state);
		if (ret)
			fprintf(stderr, "Cannot set tty state\n");
	}

Annotation

• Immediate include surface: `errno.h`, `fcntl.h`, `poll.h`, `stdbool.h`, `stdio.h`, `stdlib.h`, `string.h`, `termios.h`.
• Detected declarations: `function uhid_write`, `function create`, `function destroy`, `function handle_output`, `function event`, `function send_event`, `function keyboard`, `function main`.
• Atlas domain: Support Tooling And Documentation / samples.
• Implementation status: source implementation candidate.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.