Problem with strings.....

Guest · Posted: Mon Jun 29, 2009 3:05 pm

Hi All,

I've been using CCS C for a while now, but haven't done much with strings. Now, I have a need and can't seem to get a particular function working correctly.

I have a global string variable containing comma separated data (it happens to be NMEA GPS data). I'd like to call a subroutine, and pass as an argument a comma position. The subroutine would then return all the data between the specified comma position, and the next comma position. I think I can write the subroutine parsing code OK, but I'm having trouble figuring out how to pass data to/from the subroutine. At the moment I'm just trying to get a very basic test case working. Here is what I am trying to do:

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

You are attempting to return a pointer to a local array.
See this thread:
http://www.ccsinfo.com/forum/viewtopic.php?t=38421

Ttelmah · Guest

Also, C, does not support directly loading strings, except in the initialisation of a variable. Strcpy...

Best Wishes

Guest · Posted: Sun Jul 05, 2009 6:50 pm

Hi All,

I made life a lot easier by declaring the temporary string, NMEA_STR[] as a global variable. My parsing routine now accepts a message number, and the routine parses the main RxBuffer[] and returns just the data that is requested in the temporary string. This works great, without a lot of (unnecessary) hurdles!

I see a lot of requests for "parsing" routines for NMEA data, and it's actually quite easy. I just loop thru RxBuffer[] counting comma's (the delimiter for NMEA data) until I reach one less than the message number I'm interested in. I then start putting the following characters into my temporary string until the next comma is found. This is then the data I've requested. Lastly, I append '\0' to the last location of the temporary string to terminate it, and I'm done.

Hehe, I wrote the entire routine in my dentists waiting room before having my teeth cleaned!

Dave