Professional C++, 4th Edition

CStandard Library Header Files

The interface to the C++ Standard Library consists of 87 header files, 26 of which present the C Standard Library. It’s often difficult to remember which header files you need to include in your source code, so this appendix provides a brief description of the contents of each header, organized into eight categories:

• The C Standard Library
• Containers
• Algorithms, iterators, and allocators
• General utilities
• Mathematical utilities
• Exceptions
• I/O streams
• Threading support library

THE C STANDARD LIBRARY

The C++ Standard Library includes almost the entire C Standard Library. The header files are generally the same, except for two points:

• The header names are <cname> instead of <name.h>.
• All the names declared in the <cname> header files are in the std namespace.

NOTE

For backward compatibility, you can still include <name.h> if you want. However, that puts the names into the global namespace instead of the std namespace, and on top of that, the use of <name.h> has been deprecated. It is recommended to avoid this feature.

The following table provides a summary of the most useful functionality. Note that it’s recommended to avoid using C functionality, and instead use equivalent C++ features whenever possible.

HEADER FILENAME	CONTENTS
<cassert>	assert() macro
<ccomplex>	Only includes <complex>. This header is deprecated since C++17.
<cctype>	Character predicates and manipulation functions, such as isspace() and tolower()
<cerrno>	Defines ...