diff options
Diffstat (limited to 'documentation/sdk-manual')
-rw-r--r-- | documentation/sdk-manual/sdk-working-projects.xml | 129 |
1 files changed, 96 insertions, 33 deletions
diff --git a/documentation/sdk-manual/sdk-working-projects.xml b/documentation/sdk-manual/sdk-working-projects.xml index 44b010db6d..d1249b83a9 100644 --- a/documentation/sdk-manual/sdk-working-projects.xml +++ b/documentation/sdk-manual/sdk-working-projects.xml | |||
@@ -233,56 +233,118 @@ | |||
233 | <title>Makefile-Based Projects</title> | 233 | <title>Makefile-Based Projects</title> |
234 | 234 | ||
235 | <para> | 235 | <para> |
236 | For Makefile-based projects, the cross-toolchain environment | 236 | Simple Makefile-based projects use and interact with the |
237 | variables established by running the cross-toolchain environment | 237 | cross-toolchain environment variables established when you run |
238 | setup script are subject to general <filename>make</filename> | 238 | the cross-toolchain environment setup script. |
239 | rules. | 239 | The environment variables are subject to general |
240 | <filename>make</filename> rules. | ||
240 | </para> | 241 | </para> |
241 | 242 | ||
242 | <para> | 243 | <para> |
243 | To illustrate this, consider the following four cross-toolchain | 244 | This section presents a simple Makefile development flow and |
244 | environment variables: | 245 | provides an example that lets you see how you can use |
245 | <literallayout class='monospaced'> | 246 | cross-toolchain environment variables to replace or override |
246 | <ulink url='&YOCTO_DOCS_REF_URL;#var-CC'>CC</ulink>="i586-poky-linux-gcc -m32 -march=i586 --sysroot=/opt/poky/&DISTRO;/sysroots/i586-poky-linux" | 247 | variables used in your Makefile. |
247 | <ulink url='&YOCTO_DOCS_REF_URL;#var-LD'>LD</ulink>="i586-poky-linux-ld --sysroot=/opt/poky/&DISTRO;/sysroots/i586-poky-linux" | 248 | <imagedata fileref="figures/sdk-makefile-flow.png" width="6in" height="7in" align="center" /> |
248 | <ulink url='&YOCTO_DOCS_REF_URL;#var-CFLAGS'>CFLAGS</ulink>="-O2 -pipe -g -feliminate-unused-debug-types" | 249 | </para> |
249 | <ulink url='&YOCTO_DOCS_REF_URL;#var-CXXFLAGS'>CXXFLAGS</ulink>="-O2 -pipe -g -feliminate-unused-debug-types" | 250 | |
250 | </literallayout> | 251 | <para> |
251 | Now, consider the following three cases: | 252 | The main point of this section is to explain the following three |
253 | cases regarding variable behavior: | ||
252 | <itemizedlist> | 254 | <itemizedlist> |
253 | <listitem><para> | 255 | <listitem><para> |
254 | <emphasis>Case 1 - No Variables Set in the | 256 | <emphasis>Case 1 - No Variables Set in the |
255 | <filename>Makefile</filename>:</emphasis> | 257 | <filename>Makefile</filename> that Map to Equivalent |
256 | Because these variables are not specifically set in the | 258 | Environment Variables Set in the SDK Setup Script:</emphasis> |
259 | Because matching variables are not specifically set in the | ||
257 | <filename>Makefile</filename>, the variables retain their | 260 | <filename>Makefile</filename>, the variables retain their |
258 | values based on the environment. | 261 | values based on the environment setup script. |
259 | </para></listitem> | 262 | </para></listitem> |
260 | <listitem><para> | 263 | <listitem><para> |
261 | <emphasis>Case 2 - Variables Set in the | 264 | <emphasis>Case 2 - Variables Are Set in the Makefile that |
262 | <filename>Makefile</filename>:</emphasis> | 265 | Map to Equivalent Environment Variables from the SDK |
263 | Specifically setting variables in the | 266 | Setup Script:</emphasis> |
267 | Specifically setting matching variables in the | ||
264 | <filename>Makefile</filename> during the build results in | 268 | <filename>Makefile</filename> during the build results in |
265 | the environment settings of the variables being | 269 | the environment settings of the variables being |
266 | overwritten. | 270 | overwritten. |
271 | In this case, the variables you set in the | ||
272 | <filename>Makefile</filename> are used. | ||
267 | </para></listitem> | 273 | </para></listitem> |
268 | <listitem><para> | 274 | <listitem><para> |
269 | <emphasis>Case 3 - Variables Set when the | 275 | <emphasis>Case 3 - Variables Are Set Using the Command Line |
270 | <filename>Makefile</filename> is Executed from the | 276 | that Map to Equivalent Environment Variables from the |
271 | Command Line:</emphasis> | 277 | SDK Setup Script:</emphasis> |
272 | Executing the <filename>Makefile</filename> from the | 278 | Executing the <filename>Makefile</filename> from the |
273 | command-line results in the variables being overwritten | 279 | command line results in the environment settings of the |
274 | with command-line content regardless of what is being set | 280 | variables being overwritten. |
275 | in the <filename>Makefile</filename>. | 281 | In this case, the command-line content is used. |
276 | In this case, environment variables are not considered | 282 | <note> |
277 | unless you use the "-e" flag during the build: | 283 | The one exception to this is if you use the following |
278 | <literallayout class='monospaced'> | 284 | command-line option: |
279 | $ make -e <replaceable>file</replaceable> | 285 | <literallayout class='monospaced'> |
280 | </literallayout> | 286 | $ make -e <replaceable>target</replaceable> |
281 | If you use this flag, then the environment values of the | 287 | </literallayout> |
282 | variables override any variables specifically set in the | 288 | Using the "-e" option with <filename>make</filename> |
283 | <filename>Makefile</filename>. | 289 | causes the environment variables to be used during |
290 | the build. | ||
291 | </note> | ||
284 | </para></listitem> | 292 | </para></listitem> |
285 | </itemizedlist> | 293 | </itemizedlist> |
294 | </para> | ||
295 | |||
296 | <para> | ||
297 | The remainder of this section presents a simple Makefile example | ||
298 | that demonstrates these variable behaviors. | ||
299 | </para> | ||
300 | |||
301 | <para> | ||
302 | In a new shell environment variables are not established for the | ||
303 | SDK until you run the setup script. | ||
304 | For example, the following commands show null values for four | ||
305 | variables that are set when you run the SDK environment setup | ||
306 | script for a 64-bit build host and an i586-tuned target | ||
307 | architecture for a <filename>core-image-sato</filename> image | ||
308 | using the current &DISTRO; Yocto Project release: | ||
309 | <literallayout class='monospaced'> | ||
310 | $ echo ${CC} | ||
311 | |||
312 | $ echo ${LD} | ||
313 | |||
314 | $ echo ${CFLAGS} | ||
315 | |||
316 | $ echo ${CXXFLAGS} | ||
317 | </literallayout> | ||
318 | Running the setup script and then echoing the variables shows the | ||
319 | values established for the SDK: | ||
320 | <literallayout class='monospaced'> | ||
321 | $ source /opt/poky/2.5/environment-setup-i586-poky-linux | ||
322 | $ echo ${CC} | ||
323 | i586-poky-linux-gcc -m32 -march=i586 --sysroot=/opt/poky/2.5/sysroots/i586-poky-linux | ||
324 | $ echo ${LD} | ||
325 | i586-poky-linux-ld --sysroot=/opt/poky/2.5/sysroots/i586-poky-linux | ||
326 | $ echo ${CFLAGS} | ||
327 | -O2 -pipe -g -feliminate-unused-debug-types | ||
328 | $ echo ${CXXFLAGS} | ||
329 | -O2 -pipe -g -feliminate-unused-debug-types | ||
330 | </literallayout> | ||
331 | </para> | ||
332 | |||
333 | <para role='writernotes'> | ||
334 | NEED REST OF THE EXAMPLE. | ||
335 | WORKING ON GETTING IT TO WORK PROPERLY. | ||
336 | </para> | ||
337 | |||
338 | <!-- | ||
339 | To illustrate this, consider the following four cross-toolchain | ||
340 | environment variables: | ||
341 | <literallayout class='monospaced'> | ||
342 | <ulink url='&YOCTO_DOCS_REF_URL;#var-CC'>CC</ulink>="i586-poky-linux-gcc -m32 -march=i586 &DASH;&DASH;sysroot=/opt/poky/&DISTRO;/sysroots/i586-poky-linux" | ||
343 | <ulink url='&YOCTO_DOCS_REF_URL;#var-LD'>LD</ulink>="i586-poky-linux-ld &DASH;&DASH;sysroot=/opt/poky/&DISTRO;/sysroots/i586-poky-linux" | ||
344 | <ulink url='&YOCTO_DOCS_REF_URL;#var-CFLAGS'>CFLAGS</ulink>="-O2 -pipe -g -feliminate-unused-debug-types" | ||
345 | <ulink url='&YOCTO_DOCS_REF_URL;#var-CXXFLAGS'>CXXFLAGS</ulink>="-O2 -pipe -g -feliminate-unused-debug-types" | ||
346 | </literallayout> | ||
347 | Now, consider the following three cases: | ||
286 | <note> | 348 | <note> |
287 | For information on the variables set up by the cross-toolchain | 349 | For information on the variables set up by the cross-toolchain |
288 | environment setup script, see the | 350 | environment setup script, see the |
@@ -290,6 +352,7 @@ | |||
290 | section. | 352 | section. |
291 | </note> | 353 | </note> |
292 | </para> | 354 | </para> |
355 | --> | ||
293 | </section> | 356 | </section> |
294 | </chapter> | 357 | </chapter> |
295 | <!-- | 358 | <!-- |