ISO/IEC 9899:2011, commonly known as C11, is an international standard that defines the C programming language. It specifies the syntax, semantics, and library functions of C, ensuring consistency and portability across different platforms and compilers. This version introduced several new features, such as multi-threading support and improved type-generic programming. The standard is maintained by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). It serves as a guideline for developers and organizations to create reliable and efficient software using the C language, promoting best practices in programming.