Parameter evaluation order
Arguments to a function are not evaluated in left-to-right order, as one would imagine. The order of evaluation (and the order of execution of side effects) is unspecified.
In the following code, it's possible that ++x will be evaluated before x, and the function could print 1 1:
int x = 0;
printf("%d %d", x, ++x);Comma operator
The comma operator evaluates the first operand, discards the result, then evaluates the second operand (not the other way around). The following statements assigns 2 to x:
x = (1, 2);It is guaranteed that all the side effects of the first expression will be completed before any side effect of the second expression is performed.
Compiler flags
Visual Studio (MSVC) flags:
/external:anglebrackets /external:W0– Disable warnings for all headers included using<>.
sizeof
The sizeof operator does not evaluate its operand, so sizeof(*p) does not actually dereference the pointer.