Enter the one-time block of code. Return true if the one-time block of code has been entered, and false if the one-time block of code has already been executed. If this function returns false then the thread of execution in which enter returned true has already called leave -- i.e., the one-time block of code is guaranteed to have completed execution. The behavior is undefined unless this object was originally initialized to BSLS_BSLONCE_INITIALIZER. Note that a successful enter locks a spin-lock; it is imperative that leave be called quickly.
Declared in <bsls_bslonce.h>
bool
enter();