Difference between revisions of "cpp/header"
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− | [[cpp/experimental|C++ TR/TS's]] also define several collections of headers. | + | [[cpp/experimental|C++ TR's/TS's]] also define several collections of headers. |
===See also=== | ===See also=== |
Revision as of 03:57, 22 August 2019
The interface of C++ standard library is defined by the following collection of headers.
C compatibility headers
For some of the C standard library headers of the form xxx.h, the C++ standard library both includes an identically-named header and another header of the form cxxx (all meaningful cxxx headers are listed above).
With the exception of complex.h, each xxx.h header included in the C++ standard library places in the global namespace each name that the corresponding cxxx header would have placed in the std namespace.
These headers are allowed to also declare the same names in the std namespace, and the corresponding cxxx headers are allowed to also declare the same names in the global namespace: including <cstdlib> definitely provides std::malloc and may also provide ::malloc. Including <stdlib.h> definitely provides ::malloc and may also provide std::malloc. This applies even to functions and function overloads that are not part of C standard library.
<assert.h> (deprecated)
|
behaves as if each name from <cassert> is placed in global namespace |
<ctype.h> (deprecated)
|
behaves as if each name from <cctype> is placed in global namespace |
<errno.h> (deprecated)
|
behaves as if each name from <cerrno> is placed in global namespace |
<fenv.h> (deprecated)
|
behaves as if each name from <cfenv> is placed in global namespace |
<float.h> (deprecated)
|
behaves as if each name from <cfloat> is placed in global namespace |
<inttypes.h> (deprecated)
|
behaves as if each name from <cinttypes> is placed in global namespace |
<limits.h> (deprecated)
|
behaves as if each name from <climits> is placed in global namespace |
<locale.h> (deprecated)
|
behaves as if each name from <clocale> is placed in global namespace |
<math.h> (deprecated)
|
behaves as if each name from <cmath> is placed in global namespace except for names of mathematical special functions |
<setjmp.h> (deprecated)
|
behaves as if each name from <csetjmp> is placed in global namespace |
<signal.h> (deprecated)
|
behaves as if each name from <csignal> is placed in global namespace |
<stdarg.h> (deprecated)
|
behaves as if each name from <cstdarg> is placed in global namespace |
<stddef.h> (deprecated)
|
behaves as if each name from <cstddef> is placed in global namespace except for names of std::byte and related functions
|
<stdint.h> (deprecated)
|
behaves as if each name from <cstdint> is placed in global namespace |
<stdio.h> (deprecated)
|
behaves as if each name from <cstdio> is placed in global namespace |
<stdlib.h> (deprecated)
|
behaves as if each name from <cstdlib> is placed in global namespace |
<string.h> (deprecated)
|
behaves as if each name from <cstring> is placed in global namespace |
<time.h> (deprecated)
|
behaves as if each name from <ctime> is placed in global namespace |
<uchar.h> (deprecated)
|
behaves as if each name from <cuchar> is placed in global namespace |
<wchar.h> (deprecated)
|
behaves as if each name from <cwchar> is placed in global namespace |
<wctype.h> (deprecated)
|
behaves as if each name from <cwctype> is placed in global namespace |
Empty C headers
The headers <complex.h>
, <ccomplex>
, <tgmath.h>
, and <ctgmath>
do not contain any content from the C standard library and instead merely include other headers from the C++ standard library. The use of all these headers is deprecated in C++.
<ccomplex> (since C++11)(deprecated in C++17)(removed in C++20)
|
simply includes the header <complex> |
<complex.h> (deprecated)
|
simply includes the header <complex> |
<ctgmath> (since C++11)(deprecated in C++17)(removed in C++20)
|
simply includes the headers <complex> and <cmath>: the overloads equivalent to the contents of the C header tgmath.h are already provided by those headers
|
<tgmath.h> (deprecated)
|
simply includes the headers <complex> and <cmath> |
Meaningless C headers
The headers <ciso646>
, <cstdalign>
, and <cstdbool>
are meaningless in C++ because the macros they provide in C are language keywords in C++.
<ciso646> (removed in C++20)
|
empty header. The macros that appear in iso646.h in C are keywords in C++
|
<iso646.h> (deprecated)
|
has no effect |
<cstdalign> (since C++11)(deprecated in C++17)(removed in C++20)
|
defines one compatibility macro constant |
<stdalign.h> (deprecated)
|
defines one compatibility macro constant |
<cstdbool> (since C++11)(deprecated in C++17)(removed in C++20)
|
defines one compatibility macro constant |
<stdbool.h> (deprecated)
|
defines one compatibility macro constant |
Unsupported C headers
The C headers <stdatomic.h>
, <stdnoreturn.h>
, and <threads.h>
are not included in C++ and have no cxxx equivalents.
Experimental libraries
C++ TR's/TS's also define several collections of headers.
See also
C documentation for C Standard Library headers
|