c++cstandardsc++-faq

Where do I find the current C or C++ standard documents?

For many questions the answer seems to be found in "the standard". However, where do we find that? Preferably online.

Googling can sometimes feel futile, again especially for the C standards, since they are drowned in the flood of discussions on programming forums.

To get this started, since these are the ones I am searching for right now, where are there good online resources for:

Solution

  • PDF versions of the standard

    As of 1st September 2014 March 2022, the best locations by price for the official C and C++ standards documents in PDF seem to be:

    Non-PDF electronic versions of the standard

    Warning: most copies of standard drafts are published in PDF format, and errors may have been introduced if the text/HTML was transcribed or automatically generated from the PDF.

    (The site hosting the plain text version of the C++11 working draft also has some C++14 drafts in this format. But none of them are copies of the final working draft, N4140.)

    Print versions of the standard

    Print copies of the standards are available from national standards bodies and ISO but are very expensive.

    If you want a hard copy of the C90 standard for much less money than above, you may be able to find a cheap used copy of Herb Schildt's book The Annotated ANSI Standard at Amazon, which contains the actual text of the standard (useful) and commentary on the standard (less useful - it contains several dangerous and misleading errors).

    The C99 and C++03 standards are available in book form from Wiley and the BSI (British Standards Institute):

    Standards committee draft versions (free)

    The working drafts for future standards are often available from the committee websites:

    If you want to get drafts from the current or earlier C/C++ standards, there are some available for free on the internet:

    For C:

    For C++:

    Note that these documents are not the same as the standard, though the versions just prior to the meetings that decide on a standard are usually very close to what is in the final standard. The FCD (Final Committee Draft) versions are password protected; you need to be on the standards committee to get them.

    Even though the draft versions might be very close to the final ratified versions of the standards, some of this post's editors would strongly advise you to get a copy of the actual documents — especially if you're planning on quoting them as references. Of course, starving students should go ahead and use the drafts if strapped for cash.

    It appears that, if you are willing and able to wait a few months after ratification of a standard, to search for "INCITS/ISO/IEC" instead of "ISO/IEC" when looking for a standard is the key. By doing so, one of this post's editors was able to find the C11 and C++11 standards at reasonable prices. For example, if you search for "INCITS/ISO/IEC 9899:2011" instead of "ISO/IEC 9899:2011" on webstore.ansi.org you will find the reasonably priced PDF version.

    The site https://wg21.link/ provides short-URL links to the C++ current working draft and draft standards, and committee papers:

    The current draft of the standard is maintained as LaTeX sources on Github. These sources can be converted to HTML using cxxdraft-htmlgen. The following sites maintain HTML pages so generated:

    Tim Song also maintains generated HTML and PDF versions of the Networking TS and Ranges TS.

    POSIX extensions to the C standard

    The POSIX standard (IEEE 1003.1) requires a compliant operating system to include a C compiler. This compiler must in turn be compliant with the C standard, and must also support various extensions defined in the "System Interfaces" section of POSIX (such as the off_t data type, the <aio.h> header, the clock_gettime() function and the _POSIX_C_SOURCE macro.)

    So if you've tried to look up a particular function, been informed "This function is part of POSIX, not the C standard", and wondered why an operating system standard was mandating compiler features and language extensions... now you know!