This document lists and describes various C/C++ header files for general purpose utilities, signal handling, variable argument handling, context saving, runtime type information, time functions, floating point environment access, character testing, floating point value ranges, integer value ranges, and mathematical functions overloaded for different floating point types.

1. Header file
1. <Cstdlib> general purpose utilities,
2. <Csignal>function and macro constant for single
management
3. <Cstdarg>handling a variable length
4. <csetjmp>save executed contaxt
5. <typeinfo>run time type utilities
6. <ctime> ctime style
7. <cfenv> floting point envirement acces function
8. Toascii<ch> return ascii cod for ch
9. <ispunct(ch)>return true if ch is a punctuation character
10. Isspace(ch) return true if ch is a whitespace
11. Islower(ch) return true if ch is a lowercase letter
12. Isgraph(ch) return true if ch is aprintable and nonblank
13. Iscntrl(ch) return true if ch is a control characters
14. Isdigit(ch) return true if ch is a decimal digit
15. Isxdigit(ch) return true if ch is a hexidecimal digits
16. (floats.h) define name constant that specify the range of
floating point values
17. Climits(limits.h) ) define name constant that specify the
range of integer value
18. Cmath(math.h) these function are overload to
accommodate float double long double
19. Islower(ch) return true if ch is a lowercase letter
20. Isupper(ch) return true if ch is a uppercase letter