/usr/share/doc/fastdep/manual/c63.htm is in fastdep 0.16-13.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 | <HTML
><HEAD
><TITLE
>Automatically regenerating dependency information</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.74b"><LINK
REL="HOME"
TITLE="fastdep manual"
HREF="book1.htm"><LINK
REL="PREVIOUS"
TITLE="Writing a make-rule to generate dependency information"
HREF="c49.htm"><LINK
REL="NEXT"
TITLE="Adding an external dependency"
HREF="c90.htm"></HEAD
><BODY
CLASS="CHAPTER"
BGCOLOR="#FFFFFF"
TEXT="#000000"
LINK="#0000FF"
VLINK="#840084"
ALINK="#0000FF"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="3"
ALIGN="center"
>fastdep manual</TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="bottom"
><A
HREF="c49.htm"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="c90.htm"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="CHAPTER"
><H1
><A
NAME="AEN63"
>Chapter 4. Automatically regenerating dependency information</A
></H1
><P
>Every time you change a dependency relationship (for example when
you include an extra header in some source file), you have to regenerate
the dependency information manually by executing
<B
CLASS="COMMAND"
>make .depend</B
>
(as mentioned in the previous chapter deleting <TT
CLASS="FILENAME"
>.depend</TT
>
also works)</P
><P
>Off course this is very error-prone. Why don't we let make regenerate
the dependencies everytime one of the source files changes? Easy
enough :</P
><DIV
CLASS="EXAMPLE"
><A
NAME="AEN69"
></A
><P
><B
>Example 4-1. Makefile fragment to generate dependencies each time a source
file changes (wrong).</B
></P
><PRE
CLASS="PROGRAMLISTING"
>.depend: $(SOURCES)
fastdep $(SOURCES) > .depend
-include .depend</PRE
></DIV
><P
>This seems to work fine, but in fact doesn't. Suppose
one (or more) of our source files in <TT
CLASS="VARNAME"
>SOURCES</TT
>
includes a certain header <TT
CLASS="FILENAME"
>foo.h</TT
>. Now imagine
that during an edit-compile cycle we don't change
anything in the source files, but we added a new include
of <TT
CLASS="FILENAME"
>bar.h</TT
> in <TT
CLASS="FILENAME"
>foo.h</TT
>.
This means that the dependencies for each source file that
includes <TT
CLASS="FILENAME"
>foo.h</TT
> must change. However since
none of the source files themself change, make will find
that <TT
CLASS="FILENAME"
>.depend</TT
> is still up to date
and not regenerate it.
The end result is incorrect dependency information.</P
><P
>To summarize, the dependency information of a source file
not only depends on the source file itself, but also on all
files it includes. Hence the earlier makefile fragment is
incorrect.</P
><P
>To solve this problem, the info manual of GNU make proposes
a solution where the output of the dependency generator is
modified by piping it through sed. While this works for
normal dependency generators like the GNU C/C++ compiler
(and still works with fastdep), there is a much more elegant
solution in <SPAN
CLASS="APPLICATION"
>fastdep</SPAN
>.
By adding the <B
CLASS="COMMAND"
>--remakedeptarget=file</B
>
command line option fastdep will also emit a suitable
dependency line for its own output.</P
><DIV
CLASS="EXAMPLE"
><A
NAME="AEN83"
></A
><P
><B
>Example 4-2. Makefile fragment to generate dependencies each time a source
or included file changes (right).</B
></P
><PRE
CLASS="PROGRAMLISTING"
>.depend:
fastdep --remakedeptarget=.depend $(ALLSOURCES) > .depend
-include dependinfo</PRE
></DIV
><P
>The <TT
CLASS="FILENAME"
>.depend</TT
> file will now look like this : </P
><PRE
CLASS="SCREEN"
>file1.o: file1.cc \
header1.h \
header2.h \
header3.h
file2.o: file2.cc \
header1.h \
header3.h \
header4.h \
.depend: \
file1.cc \
header1.h \
header2.h \
header3.h \
file2.cc \
header4.h \</PRE
><P
>which is exactly how we want it to be.</P
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="c49.htm"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="book1.htm"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="c90.htm"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>Writing a make-rule to generate dependency information</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
> </TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>Adding an external dependency</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>
|