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><H1
><A
NAME="REF.NO-DEFINE"><SPAN
CLASS="PROPERTY"
>no_define</SPAN
></H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN4836"
></A
><H2
>Name</H2
>Property <SPAN
CLASS="PROPERTY"
>no_define</SPAN
> -- Suppress the normal generation of a preprocessor
<TT
CLASS="LITERAL"
>#define</TT
> symbol in a configuration header file.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN4841"><H2
>Synopsis</H2
><TABLE
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CLASS="SYNOPSIS"
>cdl_option <name> {
no_define
…
}</PRE
></TD
></TR
></TABLE
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4843"
></A
><H2
>Description</H2
><P
>By default all active and enabled properties result in either one or
two <TT
CLASS="LITERAL"
>#define'd</TT
> symbols in the package's
configuration header file, and this is one of the main ways in which
options can affect packages at build-time. It is possible to suppress
the default <TT
CLASS="LITERAL"
>#define's</TT
> by specifying a
<SPAN
CLASS="PROPERTY"
>no_define</SPAN
> property in the body of an option or other <SPAN
CLASS="APPLICATION"
>CDL</SPAN
> entity.
This property takes no arguments and should occur only once in a given
body. </P
><P
>The <SPAN
CLASS="PROPERTY"
>no_define</SPAN
> property is frequently used in conjunction with one of
the other header-file related properties such as <SPAN
CLASS="PROPERTY"
>define</SPAN
>. If one of
the other properties is used to export the required information to a
configuration header file then often there is little point in
exporting the default <TT
CLASS="LITERAL"
>#define</TT
> as
well — in fact there could be a name clash. The
<SPAN
CLASS="PROPERTY"
>no_define</SPAN
> property can also be useful if the sole purpose of an
option is to affect which files get built, and the default
<TT
CLASS="LITERAL"
>#define</TT
> would never get tested in any source code.
However in such cases the default <TT
CLASS="LITERAL"
>#define</TT
> is
mostly harmless and there is little to be gained by suppressing it.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4857"
></A
><H2
>Example</H2
><TABLE
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><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>cdl_component CYG_HAL_STARTUP {
display "Startup type"
flavor data
legal_values { "RAM" "ROM" }
default_value {"RAM"}
no_define
define -file system.h CYG_HAL_STARTUP
…
}</PRE
></TD
></TR
></TABLE
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4860"
></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.define-proc.html"
><SPAN
CLASS="PROPERTY"
>define_proc</SPAN
></A
> and
<A
HREF="ref.if-define.html"
><SPAN
CLASS="PROPERTY"
>if_define</SPAN
></A
>.</P
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