 In 2007, work began on another revision of the C standard, informally called "C1X" until its official publication on 2011-12-08.The C standards committee adopted guidelines to limit the adoption of new features that had not been tested by existing implementations.The C11 standard adds numerous new features to C and the library, including type generic macros, anonymous structures, improved Unicode support, atomic operations, multi-threading, and bounds-checked functions.