Lets say I have code like this:

Code:
inline int Len(char *p_chString){int length = 0;while( *p_chString++ ) ++length; return length;}

void RTrim(char *p_chString)
{
/*>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>*/
	char *buf;
/*<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<*/

	if(*p_chString == 0 || *p_chString == 0x00)	//If String Is Not Blank Or Errored
		return;

	buf = p_chString;
	buf += Len(p_chString) - 1;

	while (*buf == ' ' && Len(p_chString) )
		*buf-- = '\0';
}
Which trims spaces from the right side of a string. Now if I use it like so it works great:

Code:
	char cTemp[10];
	strncpy(cTemp," t    ",10);
	RTrim(cTemp);
Like it should. But lets say a stupid user comes along and tries this:

Code:
RTrim("SPACE    ");
Where you are not passing a variable. How can I test for that?