This class provides a guard for managing a BslOnce for the purpose of executing a block of code (only) once.

Synopsis

Declared in <bsls_bslonce.h>

class BslOnceGuard;

Member Functions

Name

Description

BslOnceGuard [constructor]

Create a guard to manage a block of code that is executed once.

~BslOnceGuard [destructor]

Destroy this guard, and if enter had been called on this object without a subsequent call to leave, then call leave to signal the completion of the one‐time block of code.

enter

Enter the one‐time block of code that is managed by the specified once. 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 once was originally initialized to BSLS_BSLONCE_INITIALIZER. Note that a successful enter locks a spin‐lock; it is imperative that leave be called quickly.

leave

Exit the one‐time block of code. The behavior is undefined unless the caller had previously called enter, and enter had returned true.

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