# MongoDB\BSON\Decimal128::__construct

(mongodb >=1.2.0)

MongoDB\BSON\Decimal128::__construct — Construct a new Decimal128

### 说明

final public MongoDB\BSON\Decimal128::__construct(string `$value`)

> 注意: MongoDB\BSON\Decimal128 is only compatible with MongoDB 3.4+. Attempting to use the BSON type with an earlier version of MongoDB will result in an error.

### 参数

`value` (string)

  A decimal string.

### 错误／异常

- Throws MongoDB\Driver\Exception\InvalidArgumentException on argument parsing errors.
- Throws MongoDB\Driver\Exception\InvalidArgumentException if `value` is not a valid decimal string.

### 示例

示例 #1 MongoDB\BSON\Decimal128::__construct() example

`<?php
var_dump(new MongoDB\BSON\Decimal128(1234.5678));
var_dump(new MongoDB\BSON\Decimal128(NAN));
var_dump(new MongoDB\BSON\Decimal128(INF));
?>`

以上示例的输出类似于：

    object(MongoDB\BSON\Decimal128)#1 (1) {
      ["dec"]=>
      string(9) "1234.5678"
    }
    object(MongoDB\BSON\Decimal128)#1 (1) {
      ["dec"]=>
      string(3) "NaN"
    }
    object(MongoDB\BSON\Decimal128)#1 (1) {
      ["dec"]=>
      string(8) "Infinity"
    }

### 参见

- » Decimal128 floating-point format
- » BSON Types

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