Re: [PATCH i2c-tools v2 2/2] i2ctransfer: Add optional message modifier flags

[Jean Delvare <jdelvare@suse.de>]

On Tue, 23 Dec 2025 14:22:43 +0100, Benoît Monin wrote:
> @@ -202,12 +209,21 @@ int main(int argc, char *argv[])
>  		case PARSE_GET_DESC:
>  			flags = 0;
>  
> -			switch (*arg_ptr++) {
> -			case 'r': flags |= I2C_M_RD; break;
> -			case 'w': break;
> -			default:
> -				fprintf(stderr, "Error: Invalid direction\n");
> -				goto err_out_with_arg;
> +			for (int done = 0; !done; ) {

For compatibility with older C compilers, please declare "done" at the
beginning of the while loop.

> +				switch (*arg_ptr++) {
> +				/* optional flags */
> +				case 'i': flags |= I2C_M_IGNORE_NAK; break;
> +				case 'n': flags |= I2C_M_NO_RD_ACK; break;
> +				case 'p': flags |= I2C_M_STOP; break;
> +				case 's': flags |= I2C_M_NOSTART; break;
> +				case 't': flags |= I2C_M_REV_DIR_ADDR; break;
> +				/* mandatory flags */

I would write "mandatory direction flag" (singular because only one can
and must be present).

> +				case 'r': flags |= I2C_M_RD; done = 1; break;
> +				case 'w': done = 1; break;
> +				default:
> +					fprintf(stderr, "Error: Invalid flag\n");
> +					goto err_out_with_arg;
> +				}
>  			}
>  
>  			if (*arg_ptr == '?') {
> 


-- 
Jean Delvare
SUSE L3 Support