C++ Support in Clang

This page tracks the status of C++ support in Clang.
Currently most of the C++ features are missing; here you can find features that are at least partially supported in Clang.

The following table is used to help track our implementation progress toward implementing the complete C++03 standard. We use a simple, somewhat arbitrary color-coding scheme to describe the relative completeness of features by section:

Not started/not evaluated Not Applicable Broken Some examples work Many examples work Nearly everything works Complete!
N/A ✓

A feature is "complete" when the appropriate Clang component (Parse, AST, Sema, CodeGen) implements the behavior described in all of the paragraphs in the relevant C++ standard. Note that many C++ features are actually described in several different sections within the standard. The major components are:

Parse
Clang is able to parse the grammar of this feature (or the grammar described by this section), but does not necessarily do anything with the parsed result. Use Clang's -fsyntax-only option to parse C++ programs.
AST
Clang builds an abstract syntax tree (AST) for the feature, but does not necessarily perform any type-checking. Use Clang's -ast-print option to print the resulting ASTs.
Sema
Clang parses and type-checks this feature and provides a well-formed AST annotated with types. Use Clang's -fsyntax-only to type-check code.
CodeGen
Clang parses, type-checks, and generates code for this feature, allowing one to compile and execute programs.

Updates to this table are welcome! Since Clang already supports much of C, and therefore much C++, many of the currently-white cells could be filled in. If you wish to do so, please compare Clang's implementation against the C++ standard and provide a patch that updates the table accordingly. Tests for the various features are also welcome!

Section Parse AST Sema CodeGen Notes
2 [lex] ✓ N/A N/A N/A
  2.1 [lex.phases] N/A N/A N/A Extended characters aren't handled.
  2.2 [lex.charset] N/A N/A N/A No support for extended characters.
  2.3 [lex.trigraph] ✓ N/A N/A N/A
  2.4 [lex.pptoken] ✓ N/A N/A N/A
  2.5 [lex.digraph] ✓ N/A N/A N/A
  2.6 [lex.token] ✓ N/A N/A N/A
  2.7 [lex.comment] N/A N/A NDR "form feed or vtab in comment" is not diagnosed. No AST representation of comments.
  2.8 [lex.header] ✓ N/A N/A N/A
  2.9 [lex.ppnumber] ✓ N/A N/A N/A
  2.10 [lex.name] N/A N/A N/A No support for extended characters
  2.11 [lex.key] ✓ N/A N/A N/A
  2.12 [lex.operators] ✓ N/A N/A N/A
  2.13 [lex.literal] ✓ N/A N/A N/A
    2.13.1 [lex.icon] ✓ N/A N/A N/A
    2.13.2 [lex.ccon] N/A N/A N/A Poor support for extended characters
    2.13.3 [lex.fcon] ✓ N/A N/A N/A
    2.13.4 [lex.string] N/A N/A N/A Poor support for extended characters
    2.13.5 [lex.bool] ✓ N/A N/A N/A
3 [basic] N/A N/A N/A N/A
  3.1 [basic.def] N/A
  3.2 [basic.def.odr]
  3.3 [basic.scope] N/A N/A ✓ N/A
    3.3.1 [basic.scope.pdecl] N/A N/A N/A See PR3184
    3.3.2 [basic.scope.local] N/A N/A N/A try-catch not implemented
    3.3.3 [basic.scope.proto] N/A N/A ✓ N/A
    3.3.4 [basic.funscope] N/A N/A ✓ N/A
    3.3.5 [basic.scope.namespace]
    3.3.6 [basic.scope.class]
    3.3.7 [basic.scope.hiding] N/A N/A ✓ N/A
  3.4 [basic.lookup] N/A N/A ✓ N/A
    3.4.1 [basic.lookup.unqual] N/A N/A N/A Many cases beyond simple global and function-local lookup don't work
    3.4.2 [basic.lookup.argdep] N/A N/A Missing support for templates, friend functions.
    3.4.3 [basic.lookup.qual] N/A N/A N/A
      3.4.3.1 [class.qual] N/A N/A N/A
      3.4.3.2 [namespace.qual] N/A N/A N/A
    3.4.4 [basic.lookup.elab]
    3.4.5 [basic.lookup.classref]
    3.4.6 [basic.lookup.udir]
  3.5 [basic.link]
  3.6 [basic.start]
    3.6.1 [basic.start.main]
    3.6.2 [basic.start.init]
    3.6.3 [basic.start.term]
  3.7 [basic.stc]
    3.7.1 [basic.stc.static]
    3.7.2 [basic.stc.auto]
    3.7.3 [basic.stc.dynamic]
      3.7.3.1 [basic.stc.dynamic.allocation]
      3.7.3.2 [basic.stc.dynamic.deallocation]
    3.7.4 [basic.stc.inherit]
  3.8 [basic.life]
  3.9 [basic.types]
    3.9.1 [basic.fundamental]
    3.9.2 [basic.compound]
    3.9.3 [basic.type.qualifier]
  3.10 [basic.lval]
4 [conv] ✓ ✓ ✓
  4.1 [conv.lval] ✓ ✓
  4.2 [conv.array] ✓ ✓ ✓
  4.3 [conv.func] ✓ ✓
  4.4 [conv.qual] ✓ ✓ ✓
  4.5 [conv.prom] ✓ ✓ ✓
  4.6 [conv.fpprom] ✓ ✓ ✓
  4.7 [conv.integral] ✓ ✓ ✓
  4.8 [conv.double] ✓ ✓ ✓
  4.9 [conv.fpint] ✓ ✓ ✓
  4.10 [conv.ptr] ✓ ✓ ✓
  4.11 [conv.mem] ✓ ✓ ✓
  4.12 [conv.bool] ✓ ✓ ✓
5 [expr] N/A N/A ✓
  5.1 [expr.prim] template-ids are not supported, name lookup is not complete
  5.2 [expr.post]
    5.2.1 [expr.sub] ✓ ✓ ✓
    5.2.2 [expr.call] ✓ ✓ Argument-dependent lookup is unsupported
    5.2.3 [expr.type.conv] ✓ ✓ Only between non-class types
    5.2.4 [expr.pseudo]
    5.2.5 [expr.ref] ✓ Cannot look up operator names, qualified-ids, or names in base classes
    5.2.6 [expr.post.incr] ✓ ✓ ✓
    5.2.7 [expr.dynamic.cast] ✓ ✓ ✓
    5.2.8 [expr.typeid] ✓ ✓ ✓
    5.2.9 [expr.static.cast] ✓ ✓ Some custom conversions don't work.
    5.2.10 [expr.reinterpret.cast] ✓ ✓ ✓
    5.2.11 [expr.const.cast] ✓ ✓ ✓
  5.3 [expr.unary]
    5.3.1 [expr.unary.op]
      5.3.1p1 Unary * ✓ ✓ ✓
      5.3.1p2-5 Unary & ✓ ✓ ✓
      5.3.1p6 Unary + ✓ ✓ ✓
      5.3.1p7 Unary - ✓ ✓ ✓
      5.3.1p8 Unary ! ✓ ✓ ✓
      5.3.1p9 Unary ~ ✓ ✓ ✓
    5.3.2 [expr.pre.incr] ✓ ✓ ✓
    5.3.3 [expr.sizeof] ✓ ✓ ✓
    5.3.4 [expr.new] ✓ ✓ operator delete is not looked up, initialization not quite correct
    5.3.5 [expr.delete] ✓ ✓ ✓
  5.4 [expr.cast] ✓ ✓ Too lenient, and may not always have correct semantics
  5.5 [expr.mptr.oper] ✓ Dereferenced member function pointers have the wrong type.
  5.6 [expr.mul] ✓ ✓ ✓
  5.7 [expr.add] ✓ ✓ ✓
  5.8 [expr.shift] ✓ ✓ ✓
  5.9 [expr.rel] ✓ ✓ ✓
  5.10 [expr.eq] ✓ ✓ ✓
  5.11 [expr.bit.and] ✓ ✓ ✓
  5.12 [expr.xor] ✓ ✓ ✓
  5.13 [expr.or] ✓ ✓ ✓
  5.14 [expr.log.and] ✓ ✓ ✓
  5.15 [expr.log.or] ✓ ✓ ✓
  5.16 [expr.cond] ✓ ✓ throw expressions not supported, type unification rules are based on C only
  5.17 [expr.ass] ✓ ✓ ✓
  5.18 [expr.comma] ✓ ✓ ✓
  5.19 [expr.const] ✓ ✓ Uses C semantics
6 [stmt.stmt] ✓ ✓ ✓
  6.1 [stmt.label] ✓ ✓ ✓
  6.2 [stmt.expr] ✓ ✓ ✓
  6.3 [stmt.block] ✓ ✓ ✓
  6.4 [stmt.select] ✓ ✓ Conversion of declarations to required types not really supported.
    6.4.1 [stmt.if] ✓ ✓ ✓
    6.4.2 [stmt.switch] ✓ ✓ ✓
  6.5 [stmt.iter] ✓ ✓ Conversion of declarations to required types not really supported.
    6.5.1 [stmt.while] ✓ ✓ ✓
    6.5.2 [stmt.do] ✓ ✓ ✓
    6.5.3 [stmt.for] ✓ ✓ ✓
  6.6 [stmt.jump] ✓ ✓ ✓
    6.6.1 [stmt.break] ✓ ✓ ✓
    6.6.2 [stmt.cont] ✓ ✓ ✓
    6.6.3 [stmt.return] ✓ ✓ ✓
    6.6.4 [stmt.goto] ✓ ✓ ✓
  6.7 [stmt.dcl] ✓ ✓ Skipping of initialization is not flagged. Existence and accessibility of destructors is not tested for.
  6.8 [stmt.ambig] ✓ ✓ ✓
7 [dcl.dcl]
  7.1 [dcl.spec] No support for friend declarations.
    7.1.1 [dcl.stc] ✓ Linkage merging has some errors.
    7.1.2 [dcl.fct.spec] ✓ ✓ ✓
    7.1.3 [dcl.typedef] ✓ ✓ ✓ Typedefs of anonymous tag types do not use the name of the typedef for linkage purposes.
    7.1.4 [dcl.friend]
    7.1.5 [dcl.type] ✓ ✓ ✓
      7.1.5.1 [dcl.type.cv] ✓ ✓ ✓
      7.1.5.2 [dcl.type.simple] Cannot parse template IDs.
      7.1.5.3 [dcl.type.elab] Cannot parse template IDs.
  7.2 [dcl.enum] ✓ ✓ ✓
  7.3 [basic.namespace] ✓ ✓ ✓
    7.3.1 [namespace.def] Cannot parse namespace aliases.
      7.3.1.1 [namespace.unnamed] ✓ ✓ Unnamed namespace members cannot be looked up.
      7.3.1.2 [namespace.memdef] ✓ ✓ The friend stuff is not supported.
    7.3.2 [namespace.alias]
    7.3.3 [namespace.udecl]
    7.3.4[namespace.udir] ✓ ✓ Example in p4 fails.
  7.4 [dcl.asm] ✓ ✓ ✓
  7.5 [dcl.link] ✓
8 [dcl.decl]
  8.1 [dcl.name]
  8.2 [dcl.ambig.res]
  8.3 [dcl.meaning]
    8.3.1 [dcl.ptr]
    8.3.2 [dcl.ref]
    8.3.3 [dcl.mptr]
    8.3.4 [dcl.array]
    8.3.5 [dcl.fct]
    8.3.6 [dcl.fct.default] Missing default arguments for templates.
  8.4 [dcl.fct.def]
  8.5 [dcl.init]
    8.5.1[dcl.init.aggr] No CodeGen for initializing non-aggregates or dynamic initialization.
    8.5.2 [dcl.init.string]
    8.5.3 [dcl.init.ref]
9 [class]
  9.1 [class.name] ✓
  9.2 [class.mem] No parser support for using declarations, or templates.
  9.3 [class.mfct] ✓
    9.3.1 [class.mfct.non-static] ✓
    9.3.2 [class.this] ✓
  9.4 [class.static] ✓
    9.4.1 [class.static.mfct] ✓
    9.4.2 [class.static.data] ✓
  9.5 [class.union] ✓ ✓ Semantic analysis does not yet check all of the requirements placed on the members of unions.
  9.6 [class.bit] ✓
  9.7 [class.nest] ✓
  9.8 [class.local] ✓
  9.9 [class.nested.type] ✓
10 [class.derived]
  10.1 [class.mi]
  10.2 [class.member.lookup]
  10.3 [class.virtual]
  10.4 [class.abstract]
11 [class.access]
  11.1 [class.access.spec]
  11.2 [class.access.base]
  11.3 [class.access.dcl]
  11.4 [class.friend]
  11.5 [class.protected]
  11.6 [class.access.virt]
  11.7 [class.paths]
  11.8 [class.access.nest]
12 [special]
  12.1 [class.ctor]
  12.2 [class.temporary]
  12.3 [class.conv]
    12.3.1 [class.conv.ctor]
    12.3.2 [class.conv.fct] Conversion functions can be declared and defined, but aren't used for anything.
  12.4 [class.dtor] Most of the semantics of destructors are unimplemented.
  12.5 [class.free]
  12.6 [class.init]
    12.6.1 [class.expl.init]
    12.6.2 [class.base.init] No actual direct initialization; implicit initialization not checked.
  12.7 [class.cdtor]
  12.8 [class.copy]
13 [over]
  13.1 [over.load] ✓ Missing name mangling.
  13.2 [over.dcl] ✓
  13.3 [over.match] ✓
    13.3.1 [over.match.funcs] ✓
      13.3.1.1 [over.match.call] ✓
        13.3.1.1.1 [over.call.func] ✓
        13.3.1.1.2 [over.call.object] ✓ Missing AST representation for the implicit conversion to a function reference/pointer
      13.3.1.2 [over.match.oper] ✓
      13.3.1.3 [over.match.ctor] ✓
      13.3.1.4 [over.match.copy] ✓
      13.3.1.5 [over.match.conv] ✓
      13.3.1.6 [over.match.ref] ✓
    13.3.2 [over.match.viable] ✓
    13.3.3 [over.match.best] ✓
      13.3.3.1 [over.best.ics] ✓
        13.3.3.1.1 [over.ics.scs] ✓
        13.3.3.1.2 [over.ics.user] ✓
        13.3.3.1.3 [over.ics.ellipsis] ✓
        13.3.3.1.4 [over.ics.ref] ✓
      13.3.3.2 [over.ics.rank] ✓
  13.4 [over.over] Error messages need some work. Without templates or using declarations, we don't have any ambiguities, so the semantic analysis is incomplete.
  13.5 [over.oper] Some overloaded operators can only be called with function syntax, e.g., operator[](x).
    13.5.1 [over.unary] N/A
    13.5.2 [over.binary] N/A
    13.5.3 [over.ass] N/A
    13.5.4 [over.call] N/A
    13.5.5 [over.sub] N/A
    13.5.6 [over.ref] N/A
    13.5.7 [over.inc] N/A
  13.6 [over.built] N/A Missing pointer-to-member versions (p11, p16) and support for the ternary operator (p24, p25).
14 [temp]
  14.1 [temp.param]
  14.2 [temp.names]
  14.3 [temp.arg]
    14.3.1 [temp.arg.type]
    14.3.2 [temp.arg.nontype]
    14.3.3 [temp.arg.template]
  14.4 [temp.type]
  14.5 [temp.decls]
    14.5.1 [temp.class]
      14.5.1.1 [temp.mem.func]
      14.5.1.2 [temp.mem.class]
      14.5.1.3 [temp.static]
    14.5.2 [temp.mem]
    14.5.3 [temp.friend]
    14.5.4 [temp.class.spec]
      14.5.5.1 [temp.class.spec.match]
      14.5.5.2 [temp.class.order]
      14.5.5.3 [temp.class.spec.mfunc]
    14.5.5 [temp.fct]
      14.5.5.1 [temp.over.link]
      14.5.5.2 [temp.func.order]
  14.6 [temp.res]
    14.6.1 [temp.local]
    14.6.2 [temp.dep]
      14.6.2.1 [temp.dep.type]
      14.6.2.2 [temp.dep.expr]
      14.6.2.3 [temp.dep.constexpr]
      14.6.2.4 [temp.dep.temp]
    14.6.3 [temp.nondep]
    14.6.4 [temp.dep.res]
      14.6.4.1 [temp.point]
      14.6.4.2 [temp.dep.candidate]
    14.6.5 [temp.inject]
  14.7 [temp.spec]
    14.7.1 [temp.inst]
    14.7.2 [temp.explicit]
    14.7.3 [temp.expl.spec]
  14.8 [temp.fct.spec]
    14.8.1 [temp.arg.explicit]
    14.8.2 [temp.deduct]
      14.8.2.1 [temp.deduct.call]
      14.8.2.2 [temp.deduct.funcaddr]
      14.8.2.3 [temp.deduct.conv]
      14.8.2.4 [temp.deduct.type]
    14.8.3 [temp.over]
15 [except]
  15.1 [except.throw]
  15.2 [except.ctor]
  15.3 [except.handle]
  15.4 [except.spec]
  15.5 [except.special]
    15.5.1 [except.terminate]
    15.5.2 [except.unexpected]
    15.5.3 [except.uncaught]
  15.6 [except.access]
16 [cpp]
  16.1 [cpp.cond]
  16.2 [cpp.include]
  16.3 [cpp.replace]
    16.3.1 [cpp.subst]
    16.3.2 [cpp.stringize]
    16.3.3 [cpp.concat]
    16.3.4 [cpp.rescan]
    16.3.5 [cpp.scope]
  16.4 [cpp.line]
  16.5 [cpp.error]
  16.6 [cpp.pragma]
  16.7 [cpp.null]
  16.8 [cpp.predefined]
A [gram]
  A.1 [gram.key]
  A.2 [gram.lex]
  A.3 [gram.basic]
  A.4 [gram.expr]
  A.5 [gram.stmt]
  A.6 [gram.dcl]
  A.7 [gram.decl]
  A.8 [gram.class]
  A.9 [gram.derived]
  A.10 [gram.special]
  A.11 [gram.over]
  A.12 [gram.temp]
  A.13 [gram.except]
  A.14 [gram.cpp]
B [implimits]
C [diff]
  C.1 [diff.iso]
    C.1.1 [diff.lex]
    C.1.2 [diff.basic]
    C.1.3 [diff.expr]
    C.1.4 [diff.stat]
    C.1.5 [diff.dcl]
    C.1.6 [diff.decl]
    C.1.7 [diff.class]
    C.1.8 [diff.special]
    C.1.9 [diff.cpp]
  C.2 [diff.library]
    C.2.1 [diff.mods.to.headers]
    C.2.2 [diff.mods.to.definitions]
      C.2.2.2 [diff.wchar.t]
      C.2.2.3 [diff.header.iso646.h]
      C.2.2.4 [diff.null]
    C.2.3 [diff.mods.to.declarations]
    C.2.4 [diff.mods.to.behavior]
      C.2.4.1 [diff.offsetof]
      C.2.4.2 [diff.malloc]
D [depr]
  D.1 [depr.incr.bool]
  D.2 [depr.static]
  D.3 [depr.access.dcl]
  D.4 [depr.string]
  D.5 [depr.c.headers]
E [extendid]
C++0x Features
Explicit conversion operators (N2437) ✓ No name mangling; ASTs don't contain calls to conversion operators