Quick question about what the statement is doing

Projects Programming
1

I'm working on using a UART for an OBDII setup. I've got some sample code and for the most part I understand what is going on. However, I'm not to clear on a statement. Here it is:

vehicleSpeed = strtol(&rxData[6],0,16)

I understand that strtol is string to integer and the &rxData[6] is pointing to the address of the variable rxData, and I believe specfically the address for the sixth place holder in the array rxData, but I'm not sure about the rest of the statement. The ,0,16 part. Any help would be greatly appreciated. I'm not the strongest programmer....

2

I have only a slow answer :confused:

The pointer to the string is set to position 6.
"&rxData[0]" is the same as "rxData", and "&rxData[6]" is a pointer to halfway in the string.

For the other parameters, find the reference:
http://www.nongnu.org/avr-libc/user-manual/group__avr__stdlib.html

The second parameter is the end pointer. It will be set to the position in the string where the strtol has stopped.
"If endptr is not NULL, strtol() stores the address of the first invalid character in *endptr.".
Instead of "NULL", a value of "0" is used. It is the same, but it is not nice to do so.

The third parameter is the base. A value of 16 is for an hexadecimal conversion.

This is the same : vehicleSpeed = strtol ( rxData + 6, NULL, 16);

3

0 means the string is terminated with a 0 (as it should be). 16 means the string is in Hexadecimal format

4

Thanks guys for the help!