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><A
NAME="REF.DEFINE-HEADER"><SPAN
CLASS="PROPERTY"
>define_header</SPAN
></H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN4123"
></A
><H2
>Name</H2
>Property <SPAN
CLASS="PROPERTY"
>define_header</SPAN
> -- Specify the configuration header file that
will be generated for a given package.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN4127"><H2
>Synopsis</H2
><TABLE
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><PRE
CLASS="SYNOPSIS"
>cdl_package <name> {
define_header <file name>
…
}</PRE
></TD
></TR
></TABLE
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4129"
></A
><H2
>Description</H2
><P
>When the configuration tools generate a build tree, one of the steps
is to output each package's configuration data to a header file. For
example the kernel's configuration data gets output to
<TT
CLASS="FILENAME"
>pkgconf/kernel.h</TT
>. This allows
each package's source code to <TT
CLASS="LITERAL"
>#include</TT
> the
appropriate header file and adapt to the choices made by the user.</P
><P
>By default the configuration tools will synthesize a file name from
the package name. This involves removing any prefix such as
<TT
CLASS="LITERAL"
>CYGPKG_</TT
>, up to and including the first underscore,
and then converting the remainder of the name to lower case. In some
cases it may be desirable to use a different header file, for example
an existing package may have been ported to <SPAN
CLASS="APPLICATION"
>eCos</SPAN
> and the source code
may already <TT
CLASS="LITERAL"
>#include</TT
> a particular file for
configuration data. In such cases a <SPAN
CLASS="PROPERTY"
>define_header</SPAN
> property can be
used to specify an alternative filename.</P
><P
>The <SPAN
CLASS="PROPERTY"
>define_header</SPAN
> property can only be used in the body of a
<TT
CLASS="LITERAL"
>cdl_package</TT
> command. It applies to a package as a whole and cannot
be used at a finer grain. The name specified in a <SPAN
CLASS="PROPERTY"
>define_header</SPAN
>
property will always be interpreted as relative to the
<TT
CLASS="FILENAME"
>include/pkgconf</TT
> sub-directory
of the install tree.</P
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
>For hardware-specific packages such as device drivers and HAL
packages, the current scheme of generating a configuration header file
name based on the package name may be abandoned. Instead all hardware
packages would send their configuration data to a single header file,
<TT
CLASS="FILENAME"
>pkgconf/hardware.h</TT
>. This would
make it easier for code to obtain details of the current hardware, but
obviously there are compatibility issues. For now it is recommended
that all hardware packages specify their configuration header file
explicitly. </P
></BLOCKQUOTE
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><H2
>Example</H2
><TABLE
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><TD
><PRE
CLASS="PROGRAMLISTING"
>cdl_package CYGPKG_HAL_ARM {
display "ARM architecture"
parent CYGPKG_HAL
hardware
include_dir cyg/hal
define_header hal_arm.h
…
}</PRE
></TD
></TR
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></A
><H2
>See Also</H2
><P
>Properties <A
HREF="ref.define.html"
><SPAN
CLASS="PROPERTY"
>define</SPAN
></A
>,
<A
HREF="ref.define-format.html"
><SPAN
CLASS="PROPERTY"
>define_format</SPAN
></A
>,
<A
HREF="ref.define-proc.html"
><SPAN
CLASS="PROPERTY"
>define_proc</SPAN
></A
>,
<A
HREF="ref.if-define.html"
><SPAN
CLASS="PROPERTY"
>if_define</SPAN
></A
>,
<A
HREF="ref.no-define.html"
><SPAN
CLASS="PROPERTY"
>no_define</SPAN
></A
> and
<A
HREF="ref.hardware.html"
><SPAN
CLASS="PROPERTY"
>hardware</SPAN
></A
>,</P
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