Compiler warning - suggest parentheses around assignment used as truth value
Be explicit - then the compiler won't warn that you perhaps made a mistake.
while ( (list = list->next) != NULL )or
while ( (list = list->next) )Some day you'll be glad the compiler told you, people do make that mistake ;)
While that particular idiom is common, even more common is for people to use = when they mean ==. The convention when you really mean the = is to use an extra layer of parentheses:
while ((list = list->next)) { // yes, it's an assignment
It's just a 'safety' warning. It is a relatively common idiom, but also a relatively common error when you meant to have == in there. You can make the warning go away by adding another set of parentheses:
while ((list = list->next))