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><H1
><A
NAME="REF.DEFINE-PROC"><SPAN
CLASS="PROPERTY"
>define_proc</SPAN
></H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN4169"
></A
><H2
>Name</H2
>Property <SPAN
CLASS="PROPERTY"
>define_proc</SPAN
> -- Use a fragment of Tcl code to output additional data to
configuration header files.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN4173"><H2
>Synopsis</H2
><TABLE
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><PRE
CLASS="SYNOPSIS"
>cdl_option <name> {
define_proc <Tcl script>
…
}</PRE
></TD
></TR
></TABLE
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4175"
></A
><H2
>Description</H2
><P
>For most configuration options it is sufficient to have an entry in
the configuration header file of the form:</P
><TABLE
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><TD
><PRE
CLASS="PROGRAMLISTING"
>#define <name> <value></PRE
></TD
></TR
></TABLE
><P
>In some cases it is desirable to perform some more complicated
processing when generating a configuration header file. There are a
number of CDL properties for this, including <SPAN
CLASS="PROPERTY"
>define_format</SPAN
> and
<SPAN
CLASS="PROPERTY"
>if_define</SPAN
>. The most flexible is <SPAN
CLASS="PROPERTY"
>define_proc</SPAN
>: this allows the
component writer to specify a Tcl script that gets invoked whenever
the configuration system generates the header file for the owning
package. The script can output anything to the header file, for
example it could generate a C data structure based on various
configuration values.</P
><P
>At the point that the <SPAN
CLASS="PROPERTY"
>define_proc</SPAN
> script is invoked there will be
two channels to open files, accessible via Tcl variables:
<TT
CLASS="LITERAL"
>cdl_header</TT
> is a channel to the current package's
own header file for example
<TT
CLASS="FILENAME"
>pkgconf/kernel.h</TT
>;
<TT
CLASS="LITERAL"
>cdl_system_header</TT
> is a channel to the global
configuration file
<TT
CLASS="FILENAME"
>pkgconf/system.h</TT
>. A typical
<SPAN
CLASS="PROPERTY"
>define_proc</SPAN
> script will use the <TT
CLASS="LITERAL"
>puts</TT
> command to
output data to one of these channels.</P
><P
><SPAN
CLASS="PROPERTY"
>define_proc</SPAN
> properties only take effect if the current option is
active and enabled. The default behavior of the configuration system
for an option with the <TT
CLASS="LITERAL"
>bool</TT
> flavor corresponds to
the following <SPAN
CLASS="PROPERTY"
>define_proc</SPAN
>:</P
><TABLE
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BGCOLOR="#E0E0F0"
WIDTH="70%"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
> cdl_option XXX {
…
define_proc {
puts $cdl_header "#define XXX 1"
}
}</PRE
></TD
></TR
></TABLE
><DIV
CLASS="WARNING"
><P
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><B
>Warning</B
></TD
></TR
><TR
><TD
ALIGN="LEFT"
><P
>In the current implementation it is not possible for a <SPAN
CLASS="PROPERTY"
>define_proc</SPAN
>
property to examine the current values of various configuration
options and adapt accordingly. This is a major limitation, and will be
addressed in future versions of the configuration tools.</P
></TD
></TR
></TABLE
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4199"
></A
><H2
>Example</H2
><TABLE
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WIDTH="70%"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>cdl_package CYGPKG_HAL_ARM_PID {
display "ARM PID evaluation board"
parent CYGPKG_HAL_ARM
define_header hal_arm_pid.h
include_dir cyg/hal
hardware
define_proc {
puts $::cdl_system_header "#define CYGBLD_HAL_TARGET_H <pkgconf/hal_arm.h>"
puts $::cdl_system_header "#define CYGBLD_HAL_PLATFORM_H <pkgconf/hal_arm_pid.h>"
puts $::cdl_header ""
puts $::cdl_header "#define HAL_PLATFORM_CPU \"ARM 7TDMI\""
puts $::cdl_header "#define HAL_PLATFORM_BOARD \"PID\""
puts $::cdl_header "#define HAL_PLATFORM_EXTRA \"\""
puts $::cdl_header ""
}
…
}</PRE
></TD
></TR
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></DIV
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CLASS="REFSECT1"
><A
NAME="AEN4202"
></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-header.html"
><SPAN
CLASS="PROPERTY"
>define_header</SPAN
></A
>,
<A
HREF="ref.if-define.html"
><SPAN
CLASS="PROPERTY"
>if_define</SPAN
></A
> and
<A
HREF="ref.no-define.html"
><SPAN
CLASS="PROPERTY"
>no_define</SPAN
></A
>.</P
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