the floating point naming explosion

The recent integration of the floating point technical specifications (TS) has had a disastrous effect on the set of reserved identifiers in C. If C2x would go through as it currently stands about 1700 identifiers that were completely unprotected and unannounced would enter the global name space and nasty conflicts with user code would become unavoidable. There have been several attempts in history to introduce scoped identifiers to C, but we can’t wait for such miracles to happen before C2x is supposed to come out.

Therefore, in a paper for WG14 that will be debated in the next meeting in Ithaca, I propose to take emergency measures and rename most of these new identifiers before they hit the public. On a complementary aspect, we propose decent names for the newly introduced floating point types.

N2426 Jens Gustedt, Contain the floating point naming explosion



The C committee (AKA WG14) has now moved to construct the next real revision of the C standard. This is commonly referred to “C2x”, where the “x” is supposed to represent the digit of the year in which this new standard will appear. The whole procedure is ruled by the C2x Charter that describes and fixes what kind of additions and improvements we want to see in C2x.

We regularly publish working drafts that includes the changes that have been added so far. Other than for the C17 process, that was a pure bug fix release, such working papers introduce normative changes and are public and so I will keep up links to the ones that I find relevant, here. The first of these  is still mostly C17, with only a few additions:

The most recent ones can be found here:

We keep a list of changes and their status here

For discussion of all of these changes and other possible features that you like (or don’t) to be included in C2x, please refer to the appropriate channels. The best is to get involved in the standard’s process by adhering to your national standards body, come to the WG14 meetings and/or subscribing to the committee’s mailing list. Please have in mind that all contributions should be constructive, we aren’t fans of abusive language, insults or denigration.

Comments for this page are switched off. If you have spotted errors or omissions, please contact me directly via mail. Plain mail, please, no twitter or alike, this is your Turing test.

Possible future additions to the C standard

There are many other ideas and documents floating around for inclusion into C2x. The following list is certainly not complete and biased by my personal preferences:

    • Ease the definition of extended integer types, see N2303
    • Add wide or bignum integer types
    • Add type generic interfaces for string functions to the C library, see N2068
    • Add general constants for all data types
    • Extend the concept of integer constant expressions (ICE)
    • Remove ATOMIC_VAR_INIT, see n2390 
    • Revise atomics, see n2389 
    • Revise threads, see n2391 
    • Revise the memory model, see N2294
    • Remove K&R function declarations and definitions
    • Remove one’s complement and sign-magnitude representations of signed integers, see N2218
    • Remove the * form of VLA function parameter declarations
    • Improve array bound propagation and checks
    • Add a new calling conventions with error return for library functions that avoids the use of errno
    • New string representations for NaNs, see N2290
    • Extend specifications for enum types, see N2008
    • Remove or deprecate Annex K, see N1969
    • Add a type aware print utility with format specification syntax similar to python
    • Add multibyte/wide string conversion functions, see N2282
    • char8_t: A type for UTF-8 characters and strings, see N2231
    • Adding the u8 character prefix, see N2198
    • Harmonizing left-shift behavior with C++, see N2161
    • __has_include for C, see N2101
    • add more TIME_ variants to timespec_get, integrate POSIX time conversion functions, see N2402
    • Add wchar_t and FILE to all headers that use them
    • Revise spelling of keywords and make them feature tests, see N2392
    • Make false and true first-class language features, see N2393
    • Add a simple specification of nullptr, similar to C++, see N2394
    • upgrade C library headers with [static 1]
    • type deduction from initializer, similar as C++’s auto
    • constexpr to evaluate expressions at compile time as in C++
    • __VA_ARGS__ comma omission and comma deletion, see N2160
    • TS 18661-3 as annex, see N2342
    • Improved Rules for Tag Compatibility, see N2366
    • Remove support for storage-class specifiers not in first position
    • Remove support for tentative definitions
    • Inline variables
    • Initializers for selection statement
    • Allow to not name parameters in function definitions