Full prototype:
int isblank(int);  
Purpose and Notes:
Used to test whether the character passed in (including the EOF character, hence int instead of char) is part of the locale-specific characters used to seperate words in a single line of text. (Tabs and spaces) (newline character is NOT included)
Returns:
int- C-style true or false based on whether the character passed into the function was a blank character according to the set locale.
Argument 1:
int- A character to be tested on whether it is a blank character used to seperate words in a single line. (Tabs and spaces in US/English)