The existence of open-source software in Europe may be under threat if companies, including Apple and Microsoft, persuade the European Parliament to expand patent protection in Europe.

Advocates of freely distributed programs are concerned that plans to extend patent protection in Europe could threaten the existence of open-source software such as Linux.

European Parliament member Michel Rocard wants to protect open-source software by limiting the scope of patent protection. He argues that coding essential for interoperation needs only copyright protection, writes Reuters.

Microsoft, Apple, and others want patent protection for portions of software used to "talk" to other programs. The problem is that, like all programs, open-source software must interact with a computer's other software to work, such as a word processor running on Windows, explains Reuters.

A software directive lacking Rocard's amendment could "be the death knell for open source software," said Thomas Vinje of Clifford Chance, who represents a number of open-source software groups.

Director of public policy for the Business Software Alliance trade association Francisco Mingorance said: "If you allow anyone to get this information for free you have no way of having any kind of license."

A European Parliament committee debates the issue today.