“Backwards” Conditionals in C [duplicate]

Answer 1

This will give a compiler error if comparison expression is mis typed as assignment expression.

For example, if you compile

if (buf = NULL) {}

the compiler says,

warning: suggest parentheses around assignment used as truth value [-Wparentheses]

but if you change it to

if (NULL = buf) {}

the compiler now says,

error: lvalue required as left operand of assignment