The ISO has just published the latest C language standard known previously as C1X and now that it has been published as C11. This is not to be confused with C++11, which is the recent upgrade to the C++ language.

The new standard replaces C99, but many of the new features are optional, making it easier for compilers to claim compliance. This seems like a very strange idea that will result in programmers not being able to rely on compliant compilers implementing some of the more attractive features of the new standard.

Non-optional features include alignment for data structures, type generic expressions for macros, multithreading, better unicode support, anonymous structures and unions and a few more improvements.

Some of the more interesting optional facilities include complex numeric types, variable length arrays, bounds checking and atomic primitives.

One issue that seems to be annoying the C community is the high price set for the PDF download of the new standard. The ISO is funded by many governments and makes use of the freely-given time of many government funded academics, yet it still feels that it has the right to charge around $300 for a PDF download. It is worth noting that the draft standard can still be read for free.

It is also worth commenting that most of the "new" features have been supported by the commonly used C compilers for some time. For example, GCC 4.6 has experimental support for some of the new features. 

More Information

ISO/IEC 9899:2011

The draft standard

C++0x approved

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