diff options
Diffstat (limited to 'doc/bitbake-user-manual/bitbake-user-manual-metadata.xml')
| -rw-r--r-- | doc/bitbake-user-manual/bitbake-user-manual-metadata.xml | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml b/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml index bb5a7f861..10b588352 100644 --- a/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml +++ b/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml @@ -294,17 +294,20 @@ rather than when the variable is actually used: <literallayout class='monospaced'> T = "123" - A := "${B} ${A} test ${T}" + A := "test ${T}" T = "456" - B = "${T} bval" + B := "${T} ${C}" C = "cval" C := "${C}append" </literallayout> In this example, <filename>A</filename> contains - "test 123" because <filename>${B}</filename> and - <filename>${A}</filename> at the time of parsing are undefined, - which leaves "test 123". - And, the variable <filename>C</filename> + "test 123", even though the final value of <filename>T</filename> + is "456". + The variable <filename>B</filename> will end up containing "456 cvalappend". + This is because references to undefined variables are preserved as is + during (immediate)expansion. This is in contrast to GNU Make, where undefined + variables expand to nothing. + The variable <filename>C</filename> contains "cvalappend" since <filename>${C}</filename> immediately expands to "cval". </para> |