Searching char array for string in C

Question

I have a string that looks like this:

"show net\r\r\nSSid=roving1\r\nChan=1\r\nAssoc=FAIL\r\nRate=12,   24Mb\r\nAuth=FAIL\r\nMode=NONE\r\nDHCP=FAIL\r\nBoot=0\r\nTime=OK\r\nLinks=0\r\n<4.00> "

This is data I receive from a peripheral device and I want to scan it for the string "Auth=FAIL". I'm querying it using the following command:

res = strstr(uart_rd, "Auth=FAIL");

however, it returns a value of 0. But if I simply issue the command:

res = strstr("nnAuth=FAILn", "Auth=FAIL");

it returns a value. What could be going wrong when it tries to search my char array uart_rd?

EDIT:

It looks like the issue was with a memset I was doing to clear the array before putting new data into it. I was filling it with 0s using the command:

memset(uart_rd,0,sizeof(uart_rd));

whereas I've now changed it to

memset(uart_rd,"",sizeof(uart_rd));

and it all seems to be working. Thanks for the help in diagnosing where my problem was though!

Answer 1

Well, this code

    char uart_rd[] = "show net\r\r\nSSid=roving1\r\nChan=1\r\nAssoc=FAIL\r\nRate=12,   24Mb\r\nAuth=FAIL\r\nMode=NONE\r\nDHCP=FAIL\r\nBoot=0\r\nTime=OK\r\nLinks=0\r\n<4.00> ";
    char *res;
    res = strstr(uart_rd, "Auth=FAIL");
    printf("%s", res);

gives this output:

Auth=FAIL
Mode=NONE
DHCP=FAIL
Boot=0
Time=OK
Links=0
<4.00>

So you better check your declarations of strings.