# CMP0010

Warning

The `OLD` behavior of this policy was removed in CMake version 4.0. This policy must be set to `NEW` by a call to `cmake_minimum_required()` or `cmake_policy()`.

Bad variable reference syntax is an error.

In CMake 2.6.2 and below, incorrect variable reference syntax such as a missing close-brace (`${FOO`) was reported but did not stop processing of CMake code. This policy determines whether a bad variable reference is an error. The `OLD` behavior for this policy is to warn about the error, leave the string untouched, and continue. The `NEW` behavior for this policy is to report an error.

If `CMP0053` is set to `NEW`, this policy has no effect and is treated as always being `NEW`.

This policy was introduced in CMake version 2.6.3. Prior to removal in CMake version 4.0, it could be set by `cmake_policy()` or `cmake_minimum_required()`. If it was not set, CMake warned, and used `OLD` behavior.