summaryrefslogtreecommitdiffstats
path: root/bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml
diff options
context:
space:
mode:
Diffstat (limited to 'bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml')
-rw-r--r--bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml15
1 files changed, 9 insertions, 6 deletions
diff --git a/bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml b/bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml
index bb5a7f861b..10b588352b 100644
--- a/bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml
+++ b/bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml
@@ -294,17 +294,20 @@
294 rather than when the variable is actually used: 294 rather than when the variable is actually used:
295 <literallayout class='monospaced'> 295 <literallayout class='monospaced'>
296 T = "123" 296 T = "123"
297 A := "${B} ${A} test ${T}" 297 A := "test ${T}"
298 T = "456" 298 T = "456"
299 B = "${T} bval" 299 B := "${T} ${C}"
300 C = "cval" 300 C = "cval"
301 C := "${C}append" 301 C := "${C}append"
302 </literallayout> 302 </literallayout>
303 In this example, <filename>A</filename> contains 303 In this example, <filename>A</filename> contains
304 "test 123" because <filename>${B}</filename> and 304 "test 123", even though the final value of <filename>T</filename>
305 <filename>${A}</filename> at the time of parsing are undefined, 305 is "456".
306 which leaves "test 123". 306 The variable <filename>B</filename> will end up containing "456 cvalappend".
307 And, the variable <filename>C</filename> 307 This is because references to undefined variables are preserved as is
308 during (immediate)expansion. This is in contrast to GNU Make, where undefined
309 variables expand to nothing.
310 The variable <filename>C</filename>
308 contains "cvalappend" since <filename>${C}</filename> immediately 311 contains "cvalappend" since <filename>${C}</filename> immediately
309 expands to "cval". 312 expands to "cval".
310 </para> 313 </para>