iso646.h

C Standard Library
Data types Character classification Strings Mathematics File input/output Date/time Localization Memory allocation Program control Miscellaneous headers: <assert.h> <errno.h> <iso646.h> <setjmp.h> <signal.h> <stdarg.h> <wchar.h>
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The iso646.h header file is part of the C standard library. It was added to this library in a 1995 amendment to the C90 standard. It defines a number of macros which allow programmers to use C language bitwise and logical operators, which, without the header file, cannot be quickly or easily typed on some international and non-QWERTY keyboards.

The filename refers to the ISO646 standard, a 7-bit character set with a number of regional variations, some of which have accented characters in place of the punctuation marks used by C operators.

The macros

The iso646.h header defines the following 11 macros as stated below:

Macro	Defined as
and	&&
and_eq	&=
bitand	&
bitor	|
compl	~
not	!
not_eq	!=
or	||
or_eq	|=
xor	^
xor_eq	^=

C++

These identifiers are operator keywords in the ISO C++ programming language and do not require the inclusion of a header file. For consistency, the C++98 standard provides the header <ciso646>. However the latter file has no effect, being empty.^[1]

See also

• Digraphs and trigraphs in C

References

1. ^ Lischner, Ray (2003). C++ in a Nutshell. O'Reilly Media. p. 212. ISBN 0-596-00298-X. 

External links

• iso646.h: alternative spellings – Base Definitions Reference, The Single UNIX® Specification, Issue 7 from The Open Group