Hi,

In a previous question, hammer-ga wrote the following function for me...

char *es_strrclip_pointer(char needle, char *haystack) 
{
char  	*endpos;
char 	*retval;

	retval = NULL;
	if(haystack != NULL)
	{
		retval = (char *)strdup(haystack);
		if(retval != NULL)
		{
			endpos = strrchr(retval, needle);
			if(endpos != NULL)
			{
				endpos++;
				*endpos = '\0';
			}
			else
			{
				retval = NULL;
				fprintf(stderr, "Needle not found in Haystack.\n");
			}
		}
		else
		{
			fprintf(stderr, "Strdup failed.\n");
		}
	}
	else
	{
		fprintf(stderr, "Haystack is NULL.\n");
	}
	return(retval);
}

I was wondering if I could get a commented version of this, so I can
get a better grip on how it works.

Thanks!
-- Quinn

Here you are:

* * * Cut Here * * *

char *es_strrclip_pointer(char needle, char *haystack) 
{
char  	*endpos;
char 	*retval;
        /* Initialize return value to null */
	retval = NULL;
        /* Make sure haystack is not null */
	if(haystack != NULL)
	{
                /* Allocate a copy of the haystack string; strdup
                ** is equivalent to:
                ** char *copy = malloc(strlen(s) + 1);
                ** strcpy(copy, s);
                */
		retval = (char *)strdup(haystack);
                /* Make sure memory allocation did not fail
		if(retval != NULL)
		{
                        /* strrchr returns a pointer to the LAST occurrence
                        ** of 'needle' in 'retval' (our copy of haystack)
                        */ 
			endpos = strrchr(retval, needle);
                        /* If the needle was found... */
			if(endpos != NULL)
			{
                                /* Move one character PAST needle... */
				endpos++;
                                /* And make that character a null, ending
                                ** the string at that point. retval is now a
                                ** copy of haystack up to and including
                                ** needle 
                                */
				*endpos = '\0';
			}
			else
			{
                                /* No needle in the haystack */
				retval = NULL;
				fprintf(stderr, "Needle not found in Haystack.\n");
			}
		}
		else
		{
                        /* Memory allocation failure */
			fprintf(stderr, "Strdup failed.\n");
		}
	}
	else
	{
                /* Haystack was a null pointer, not a valid string */
		fprintf(stderr, "Haystack is NULL.\n");
	}
        /* Return our copy of haystack up to and including needle.
        ** Returned string should eventually be freed with free() by caller
        */
	return(retval);
}

Thanks for the quick response!  The comments to the code were very
easy to understand, and cleared up everything I had been wondering
about.  Great job!