<!--
{
  "availability" : [
    "iOS: 8.0.0 -",
    "iPadOS: 8.0.0 -",
    "macCatalyst: 13.1.0 -",
    "macOS: 10.11.0 -",
    "tvOS: -",
    "visionOS: 1.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "Metal",
  "identifier" : "/documentation/Metal/MTLDevice/makeLibrary(source:options:)",
  "metadataVersion" : "0.1.0",
  "role" : "Instance Method",
  "symbol" : {
    "kind" : "Instance Method",
    "modules" : [
      "Metal"
    ],
    "preciseIdentifier" : "c:objc(pl)MTLDevice(im)newLibraryWithSource:options:error:"
  },
  "title" : "makeLibrary(source:options:)"
}
-->

# makeLibrary(source:options:)

Synchronously creates a Metal library instance by compiling the functions in a source string.

```
func makeLibrary(source: String, options: MTLCompileOptions?) throws -> any MTLLibrary
```

## Parameters

`source`

A string that contains source code for one or more Metal functions. For information about writing source in Metal Shading Language (MSL), see the [Metal Shading Language Specification](https://developer.apple.com/metal/Metal-Shading-Language-Specification.pdf).

`options`

An [`MTLCompileOptions`](/documentation/Metal/MTLCompileOptions) instance that affects the compilation of the source code in the string.

## Return Value

A new [`MTLLibrary`](/documentation/Metal/MTLLibrary) instance if the method completes successfully;
otherwise Swift throws an error and Objective-C returns `nil`.

## Discussion

Because there’s no search path to find other functions, the source may only import the Metal default library.

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)