www.delorie.com/gnu/docs/gcc/cpp_6.html   search  
 
Buy the book!


The C Preprocessor

[ < ] [ > ]   [ << ] [ Up ] [ >> ]         [Top] [Contents] [Index] [ ? ]

2.1 Include Syntax

Both user and system header files are included using the preprocessing directive `#include'. It has two variants:

#include <file>
This variant is used for system header files. It searches for a file named file in a standard list of system directories. You can prepend directories to this list with the `-I' option (see section 12. Invocation).

#include "file"
This variant is used for header files of your own program. It searches for a file named file first in the directory containing the current file, then in the same directories used for <file>.

The argument of `#include', whether delimited with quote marks or angle brackets, behaves like a string constant in that comments are not recognized, and macro names are not expanded. Thus, #include <x/*y> specifies inclusion of a system header file named `x/*y'.

However, if backslashes occur within file, they are considered ordinary text characters, not escape characters. None of the character escape sequences appropriate to string constants in C are processed. Thus, #include "x\n\\y" specifies a filename containing three backslashes. (Some systems interpret `\' as a pathname separator. All of these also interpret `/' the same way. It is most portable to use only `/'.)

It is an error if there is anything (other than comments) on the line after the file name.


  webmaster     delorie software   privacy  
  Copyright 2003   by The Free Software Foundation     Updated Jun 2003