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| Sample Programs |
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| Connection Mode |
#define GOT_CTRL | 1 | /* message has only a control part */ | |
#define GOT_DATA | 2 | /* message | has only a data part */ |
#define GOT_BOTH | 3 | /* message | has both control and data parts */ |
int |
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get_msg(fd) |
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int | fd; | /* file descriptor */ |
{ |
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int | flags = 0; | /* 0 |
int | result = 0; | /* return value */ |
/* |
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zero first byte of control area so the caller can call check_ctrl without checking the get_msg return value; if there was only data in the message and the user was expecting control or control + data, then when he calls check_ctrl it will compare the expected primitive zero and print information about the primitive that it got.
*/
ctrl_area[0] = 0;
/* call getmsg and check for an error */ if(getmsg(fd, &ctrl_buf, &data_buf, &flags) < 0) {
printf(”error: getmsg failed, errno = %d\n”, errno); exit(1);
}
if(ctrl_buf.len > 0) { result = GOT_CTRL;
}
if(data_buf.len > 0) { result = GOT_DATA;
}
return(result);
}
/************************************************************************** check that control message is the expected message
**************************************************************************/
void |
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check_ctrl(ex_prim) |
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int | ex_prim; | /* the expected primitive */ |
{ |
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dl_error_ack_t | *err_ack = (dl_error_ack_t *)ctrl_area; | |
/* did we get the expected primitive? */
/* did we get a control part */ if(ctrl_buf.len) {
/* yup; is it an ERROR_ACK? */
ex_prim);
printf(”got DL_ERROR_ACK\n”);
printf(” dl_error_primitive = 0x%02x\n”,
printf(” dl_errno = 0x%02x\n”,
printf(” dl_unix_errno = %d\n”,
Appendix A | 145 |