SPL
SplPriorityQueue::compare
SPL
PHP Manual

# The SplPriorityQueue class

## Introduction

The SplPriorityQueue class provides the main functionalities of an prioritized queue, implemented using a heap.

## Class synopsis

SplPriorityQueue
class SplPriorityQueue implements Iterator , Countable {
/* Methods */
__construct ( void )
void compare ( mixed `$priority1` , mixed `$priority1` )
int count ( void )
mixed current ( void )
mixed extract ( void )
void insert ( mixed `$value` , mixed `$priority` )
bool isEmpty ( void )
mixed key ( void )
void next ( void )
void recoverFromCorruption ( void )
void rewind ( void )
void setExtractFlags ( int `$flags` )
mixed top ( void )
bool valid ( void )
}

## Table of Contents

- SplPriorityQueue::compare — Compare priorities in order to place elements correctly in the heap while sifting up.
- SplPriorityQueue::__construct — Constructs a new empty queue
- SplPriorityQueue::count — Counts the number of elements in the queue.
- SplPriorityQueue::current — Return current node pointed by the iterator
- SplPriorityQueue::extract — Extracts a node from top of the heap and sift up.
- SplPriorityQueue::insert — Inserts an element in the queue by sifting it up.
- SplPriorityQueue::isEmpty — Checks whether the queue is empty.
- SplPriorityQueue::key — Return current node index
- SplPriorityQueue::next — Move to the next node
- SplPriorityQueue::recoverFromCorruption — Recover from the corrupted state and allow further actions on the queue.
- SplPriorityQueue::rewind — Rewind iterator back to the start (no-op)
- SplPriorityQueue::setExtractFlags — Sets the mode of extraction
- SplPriorityQueue::top — Peaks at the node from the top of the queue
- SplPriorityQueue::valid — Check whether the queue contains more nodes

SPL
SplPriorityQueue::compare
SPL
PHP Manual