C++ headers Headache

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Q: What are traditional C++ (pre-standard) headers?

A: The traditional C++ (pre-standard) headers define classes, values, macros, and functions in headers that have *.h extension. This includes non-standard STL headers with *.h extension (iostream.h, fstream.h, vector.h, etc.) and C headers with *.h extension (stdlib.h, stdio.h, etc.). Pre-standard headers have all the code in the global namespace.



Q: What are C++ standard headers?

A: C++ standard headers are those headers that are specified by the C++ standard.



Q: How do I recognize the C++ standard headers?

A: The naming scheme for these files were specified based on the naming scheme of the traditional header files, but without the ending '.h'. For example, 'fstream.h' becomes 'fstream', 'memory.h' becomes 'memory' and so on.



Q: What about 'iostream.h'?

A: The header iostream.h has never been part of the official C++ standard, which means any compiler that provides iostream.h, can do what ever it wants with it, and the compiler would still be considered compliant with the C++ standard. However, the C+ standard specifies the existence of a header within the input/output library.



Q: What about the traditional ANSI C standard header files?

A: The traditional ANSI C standard header files are prefixed with the letter 'c'. Thus 'stdio.h' has become 'cstdio', 'stdlib.h' is called 'cstdlib', 'math.h' is called 'cmath', 'time.h' is called 'ctime' and so on. This is the complete list:



assert.h - cassert

ctype.h - cctype

errno.h - cerrno

float.h - cfloat

iso646.h - ciso646

limits.h - climits

locale.h - clocale

math.h - cmath

setjmp.h - csetjmp

signal.h - csignal

stdarg.h - cstdarg

stddef.h - cstddef

stdio.h - cstdio

stdlib.h - cstdlib

string.h - cstring

time.h - ctime

wchar.h -
wtype.h - cwtype



Q: Which are the C++ standard headers?

A: Grouped on library category, here they are:

* Language support:

o Types:

o Implementation properties: , ,

o Start and termination:

* Dynamic memory management:

o Type identification:

o Exception handling:

o Other runtime support: , , , ,

* Diagnostics:

o Exception classes:

o Assertions:

o Error numbers:

* General utilities:

o Utility components:

o Function objects:

o Memory:

o Date and time:

* Strings:

o Character traits:

o String classes:

o Null-terminated sequence utilities: , , , ,

* Localization:

o Locales:

o C library locales:

* Containers:

o Sequences: , , , ,

o Associative containers: