# Errno error code

When using part of the Weixin Mini Program API / component, the exception thrown (fail callback / Promise reject)Errorobject with the exception of `` errMsg, with a generic error codeerrno`.

Code examples

wx.openBluetoothAdapter({
  success (res) {
    console.log(res)
  }
  fail (err) {
    console.log(err.errno)
  }
})

# Background Introduction

The errnoerror code appears to solve the following problems:

• At present, some APIs only return the error messageerrMsgwhen an error occurs, no error code.Another part of the API, although errCode, but no unified format specification.
• Among the current errCode APIs, different APIs return errCode granularity when they fail. The errCode granularity of some APIs is too large and not enough information.
• The same error in different API errCode misaligned, not easy for developers to remember and deal with.

Therefore, we have designed a set of error codes with a unified specificationerrnoto help developers better develop, debug and handle errors.

The errnoerror code has the following advantages:

• There is a uniform design specification for the error code format.
• The same error occurs in different APIs, and the corresponding error code is the same.
• The error code contains API category information to help developers quickly locate problems.
• The error code granularity in different APIs is more uniform.

When theErrorobject containserrnoError codes anderrCodeWhen an error code is made, generally takes precedence overerrnoerror code .

A subsequenterrnoerror code will gradually be extended to all API interfaces and replace the existingerrCodeparameter to provide developers with error messages.

# Error code design

ErrnoError codes are typically seven bits, with bits 1 - 2 identifying the first class of the API interface, bits 3 - 4 identifying the second class of the interface, and bits 5 - 7 indicating the specific error type.

Example:errnoerror code is1504003When``15indicates that the first class of the API interface is Device,04indicating that the second class of theAPI interface is DevicesNFC,003denotes specific error types.

The categories of API interfaces that have been accessed toerrnoinclude:

• Level 1 category:00- generic error code
• Level 1 category:01- Basic
  • Level 2 category:00- General Base Errors
  • Category II:03- Updated
  • Level 2:09- Encryption
• Level I category:06- Network
  • Level 2 category:00- General network errors
  • Level 2 category:02- Initiate request
  • Level 2 category:03- Download
  • Level 2:04- Upload
  • Level 2 category:06- mDNS
• Level 1 category:07- Payment
  • Category II:00- Universal Payment Errors
  • Secondary category:01- Payment default secondary category
• Level 1 category:11- Media
  • Level 2 category:07- Real time audio and video
• Category I:13- Documents
  • Level 2 category:00- Common file errors
  • Secondary category:01- File default secondary category
  • Level 2:02- fd interface
• Level 1 category:14- Open interfaces
  • Secondary category:16- WeChat Channels
• Level 1 category:15- Equipment
  • Level 2 category:00- General Equipment Error
  • Level 2 category:04- NFC
  • Level 2 category:05- Wi-Fi
  • Level 2 category:09- Bluetooth Low Energy
  • Level 2 category:10- Bluetooth ®
• Level 1 category:20- AI
  • Level 2 category:02- Face recognition
  • Level 2:03- vision kit
  • Level 2 category:04- Machine learning

The first class name is basically the same as the second class name and the class name of the API interface document.

# Best practices

In the case of the API interfaceopenBluetoothAdapter, for example, an exceptionErrorobject is flushed for theopen BluetoothAdapterinterface when the Bluetooth adapter is not available:

"err":
{
	"errMsg": "openBluetoothAdapter:fail:not available",
	"errCode": 10001,
	"errno": 1500102
}

An exception can be handled by the following code:

wx.openBluetoothAdapter({
  success (res) {
    console.log(res)
  },
  fail (err) {
    // 微信无法使用蓝牙，可引导用户在系统设置中启用蓝牙
    if ( err.errno === 1500102 ) {
        wx.showModal({
            content: '微信无法使用蓝牙，请到系统设置中启用'
        })
    }
  }
})

# List of Error Codes

Here is a glance at theerrnovalues.