In header files whether functions are declared or defined?  

well Nawraj, In header files the functions are declared not defined itz defined in the library routines only.

A header file is a file containing C declarations and macro definitions to be shared between several source files.

You request the use of a header file in your program by including it, with the C preprocessing directive `#include'.

Header files serve two purposes.

1) System header files declare the interfaces to parts of the operating system. You include them in your program to supply the definitions and declarations you need to invoke system calls and libraries.

2) Your own header files contain declarations for interfaces between the source files of your program. Each time you have a group of related declarations and macro definitions all or most of which are needed in several different source files, it is a good idea to create a header file for them.

For more info visit Source site:
http://www.redhat.com/d ocs/manuals/enterprise/RHEL-4- Manual/cpp/header-files.html

Answered by Uttam at 11:40 PM on March 27, 2008

The functions are declared

Answered by Arun Kumar at 6:20 PM on March 27, 2008

All library functions are declared in a header file. To make the contents of a header file available to your program, include the header file with an #include preprocessor directive. For example:



#include <stddef.h>




Each header file declares a set of related functions, as well as defining any types and macros needed for their use.

The standard headers are:

Diagnostics: <assert.h> ( Section 9.1)
Character processing: <ctype.h> ( Section 9.2)
Error codes: <errno.h> ( Section 9.3)
ANSI C limits: <limits.h> and <float.h> ( Section 9.4)
Localization: <locale.h> ( Section 9.5)
Mathematics: <math.h> ( Section 9.6)
Nonlocal jumps: <setjmp.h> ( Section 9.7)
Signal handling: <signal.h> ( Section 9.8)
Variable arguments: <stdarg.h> ( Section 9.9)
Common definitions: <stddef.h> ( Section 9.10)
Input/output: <stdio.h> ( Section 9.11)
General utilities: <stdlib.h> ( Section 9.12)
String processing: <string.h> ( Section 9.13)
Date and time: <time.h> ( Section 9.14)
Header files can be included in any order. Each can be included more than once in a given scope with no effect different from being included once. However, the effect of including <assert.h> depends on the definition of NDEBUG. Include headers outside of any external declaration or definition, and before any reference to the functions, types, or macros declared or defined in the headers. If an identifier is declared or defined in more than one included header, the second and subsequent headers containing that identifier can be included after the initial reference to that identifier.

For more deatils visit:
http://h30097.www3.hp. com/docs/base_doc/DOCUMENTATIO N/V50_HTML/ARH9NATE/DOCU_020.H TM

Answered by Shilpa Behl at 5:08 PM on March 27, 2008

In header files the functions are declared not defined, it is defined in the library routines only.

Answered by Chaitanya at 4:53 PM on March 27, 2008

nawraj In header files the functions are declared not defined itz defined in the library routines only

Answered by varadaraju at 4:51 PM on March 27, 2008

Well Nawraj, system defined header files only contains the declarations of functions.

A header file is a file containing C declarations and macro definitions to be shared between several source files.

You request the use of a header file in your program by including it, with the C preprocessing directive `#include'.

Header files serve two purposes.

1) System header files declare the interfaces to parts of the operating system. You include them in your program to supply the definitions and declarations you need to invoke system calls and libraries.

2) Your own header files contain declarations for interfaces between the source files of your program. Each time you have a group of related declarations and macro definitions all or most of which are needed in several different source files, it is a good idea to create a header file for them.

Answered by Alok Gupta at 2:50 PM on March 27, 2008

Functions in C are declared in header files. The body of a function has it's own .c file (extracted from a library at run-time).

Answered by swadesh at 1:35 PM on March 27, 2008

in hadder files function r defined

Answered by ankit pandey at 1:27 PM on March 27, 2008