fscanf for streamed I/O

I am in the process of porting some legacy code to vxworks and am
running into problems with reading from the port.

Here is what I have:

void test_routine()
{
    FILE *read;
    char buffer[300];

    if ((read = fopen("/tyCo/0", "r")) == NULL)
	printf("Packet INPUT port did not open");
    if (setvbuf(read, NULL, _IONBF, NULL))	/* unbuffered */
	printf("setvbuff(read, NULL, _IONBF, NULL) failed\n");

    while(1) {
 	fscanf(read, "\002%[^\003]\003",buffer); 	/* <STX>data<ETX> */
                printf("%s\n",buffer);
        }
}

This code always lags by one packet...
   * I send packet_A
        -->  no output
   * I send packet_B
        -->  packet_A displayed
   * I send packet_C
        -->  packet_B displayed
   * I send packet_D
        -->  packet_C displayed

Any ideas??  (We are attempting to continue using this same code on our
existing system, so I'd like to avoid completely rewriting it.)

jimzat

.

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