# shmop_read

(PHP 4 >= 4.0.4, PHP 5, PHP 7)

shmop_read — Read data from shared memory block

### 说明

shmop_read ( resource `$shmid` , int `$start` , int `$count` ) : string

shmop_read() will read a string from shared memory block.

### 参数

`shmid`

  The shared memory block identifier created by shmop_open()

`start`

  Offset from which to start reading

`count`

  The number of bytes to read. 0 reads `shmop_size($shmid) - $start` bytes.

### 返回值

Returns the data 或者在失败时返回 `FALSE`.

### 更新日志

版本 | 说明
--- | ---
7.0.0 | The type of `shmid` has been changed from int to resource.

### 范例

Example #1 Reading shared memory block

    <?php
    $shm_data = shmop_read($shm_id, 0, 50);
    ?>

This example will read 50 bytes from shared memory block and place the data inside $shm_data.

### 参见

- shmop_write() - Write data into shared memory block