[ Note: The header <cstdlib> ([cstdlib.syn]) declares the functions described in this subclause. — end note ]
Effects: The rand and srand functions have the semantics specified in the C standard library.
Remarks: The implementation may specify that particular library functions may call rand. It is implementation-defined whether the rand function may introduce data races ([res.on.data.races]). [ Note: The other random number generation facilities in this standard ([rand]) are often preferable to rand, because rand's underlying algorithm is unspecified. Use of rand therefore continues to be non-portable, with unpredictable and oft-questionable quality and performance. — end note ]
See also: ISO C 7.22.2