need C help, passing char buffer[] by-value....

Brad Mettee bmettee at
Mon Oct 19 05:48:41 UTC 2009

Gary Kline wrote:
> Guys,
> maybe this can't be done reading in a file with fgets(buffer[128], fp),
> then calling skiptags(), conditionally, to while () past ',' and '>'.
> I know I need to calll skipTags with its address, skipTags(&buffer);, but then how to i
> handle the variable "s" in skipTags?  Anybody?
> // redo, skip TAGS
> skipTags((char *)&s)
> {
>         if (*s == '<')
>         {
>                 while (*s != '>')
>                 {
>                         s++;
>                 }
>                 s++;
>         }
> }
Your function may not work exactly as you think it will. Your basic idea 
runs on the assumption that the tag will never be broken during the file 
read. It's possible that you'll read "some data<Tag begin" and the next 
read will have ">more data here<tag ends>", or some variation thereof. 
If you know for a fact that the string you read in will always be 
complete, then what's below should work fine:

// where *s is the address of a string to be parsed
// maxlen represents the maximum number of chars potentially in the string and is not zero based (ie: maxlen 256 = char positions 0-255)
// *curpos is the current position of the pointer (this prevents bounds errors)
skipTags(char *s, long maxlen, long *curpos)
        if (*s == '<')
                while (*s != '>' && && *s && *curpos < maxlen)
		if (*curpos < maxlen)

When you read in the next line of the file, reset curpos to zero, set 
maxlen to number of bytes read. As you process each char after the 
function is called, you'll need to increment curpos as well.

Depending on the size of the files you are reading, you may be able to 
read the entire file into memory at once and avoid any possible TAG 

If you explain exactly what you're trying to accomplish, we may be able 
to come up with an easier/cleaner solution.

(warning: none of the above code is tested, but in concept it should 
work ok)

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