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><H1
><A
NAME="REF.MAKE-OBJECT"><SPAN
CLASS="PROPERTY"
>make_object</SPAN
></H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN4770"
></A
><H2
>Name</H2
>Property <SPAN
CLASS="PROPERTY"
>make_object</SPAN
> -- Define a custom build step, resulting in an object file
that should go into a library.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN4774"><H2
>Synopsis</H2
><TABLE
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><TR
><TD
><PRE
CLASS="SYNOPSIS"
>cdl_option <name> {
make_object [-library=<library>] [-priority=<pri>] {
<custom build step>
}
…
}</PRE
></TD
></TR
></TABLE
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4776"
></A
><H2
>Description</H2
><P
>When building an <SPAN
CLASS="APPLICATION"
>eCos</SPAN
> configuration the primary target is a single
library, <TT
CLASS="FILENAME"
>libtarget.a</TT
>. Most of the object files
which go into this library will be generated as a result of <SPAN
CLASS="PROPERTY"
>compile</SPAN
>
properties. Occasionally it may be necessary to have special build
steps for a given object file, and this can be achieved with a
<SPAN
CLASS="PROPERTY"
>make_object</SPAN
> property. The use of this property should be avoided
whenever possible because it greatly increases the risk of portability
problems, both on the host side because of possible problems with the
tools, and on the target side because a custom build step may not
allow adequately for the wide variety of architectures supported by
<SPAN
CLASS="APPLICATION"
>eCos</SPAN
>.</P
><P
>The <SPAN
CLASS="PROPERTY"
>make_object</SPAN
> property takes a single argument, which resembles a
makefile rule: it consists of a target, a list of dependencies, and
one or more commands that should be executed. The target should be an
object file. However the <SPAN
CLASS="PROPERTY"
>make_object</SPAN
> argument is not a makefile
fragment, and custom build steps may get executed in build
environments that do not involve make. For full details of custom
build steps see <A
HREF="build.make.html#BUILD.CUSTOM"
>the Section called <I
>Custom Build Steps</I
> in Chapter 4</A
>.</P
><DIV
CLASS="WARNING"
><P
></P
><TABLE
CLASS="WARNING"
BORDER="1"
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><TR
><TD
ALIGN="CENTER"
><B
>Warning</B
></TD
></TR
><TR
><TD
ALIGN="LEFT"
><P
>The exact syntax and limitations of custom build steps have not yet
been finalized, and may change in future versions of the
configuration tools.</P
></TD
></TR
></TABLE
></DIV
><P
>The <SPAN
CLASS="PROPERTY"
>make_object</SPAN
> property takes an optional library argument. If no
library is specified then the default library for the current package
will be used, which will be <TT
CLASS="FILENAME"
>libtarget.a</TT
> unless
the <TT
CLASS="LITERAL"
>cdl_package</TT
> command contains a <SPAN
CLASS="PROPERTY"
>library</SPAN
> property.</P
><P
>The <SPAN
CLASS="PROPERTY"
>make_object</SPAN
> property also takes an optional priority argument
indicating the order in which build steps take place. This priority
complements the dependency list, and avoids problems with packages
needing to know details of custom build steps in other packages (which
may change between releases). The defined order is:</P
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
>Priority 0</DT
><DD
><P
>The header files exported by the current set of packages are copied
to the appropriate places in the
<TT
CLASS="FILENAME"
>include</TT
> subdirectory of the
install tree. Any unnecessary copies are avoided, to prevent rebuilds
of package and application source modules caused by header file dependencies.</P
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
>A possible future enhancement of the build system may result in the
build and install trees being updated automatically if there has been
a change to the <TT
CLASS="FILENAME"
>ecos.ecc</TT
> configuration savefile.</P
></BLOCKQUOTE
></DIV
></DD
><DT
>Priority 100</DT
><DD
><P
>All files specified in <SPAN
CLASS="PROPERTY"
>compile</SPAN
> properties will get built, producing
the corresponding object files. In addition any custom build steps
defined by <SPAN
CLASS="PROPERTY"
>make_object</SPAN
> properties get executed, unless there is a
<TT
CLASS="LITERAL"
>-priority=</TT
> option.</P
></DD
><DT
>Priority 200</DT
><DD
><P
>The libraries now get built using the appropriate object files.</P
></DD
><DT
>Priority 300</DT
><DD
><P
>Any custom build steps specified by <SPAN
CLASS="PROPERTY"
>make</SPAN
> properties now get
executed, unless the priority for a particular build step is changed
from its default.</P
></DD
></DL
></DIV
><P
>For example, if a custom build step needs to take place before any of
the normal source files get compiled then it should be given a
priority somewhere between 0 and 100. If a custom build step involves
post-processing an object file prior to its incorporation into a
library then a priority between 100 and 200 should be used. It is not
sensible to have a priority above 200, since that would imply building
an additional object file for a library that has already been created.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4823"
></A
><H2
>Example</H2
><TABLE
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><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>cdl_option XXX {
…
make_object {
parser.o: parser.y
yacc $<
$(CC) $(CFLAGS) -o $@ y.tab.c
}
}</PRE
></TD
></TR
></TABLE
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4826"
></A
><H2
>See Also</H2
><P
>Properties <A
HREF="ref.compile.html"
>compile</A
>,
<A
HREF="ref.make.html"
>make</A
> and
<A
HREF="ref.library.html"
>library</A
>.</P
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