GNU Make

(2 intermediate revisions by the same user not shown)

Line 19:

** If <tt>svn:ignore</tt> is properly used, the following rule suffices as a project-independent <tt>clean</tt> target, assuming the presence of [[xmlstarlet]]:<pre>svn --xml --no-ignore status | xmlstarlet sel -t -m //entry -i "wc-status[@item='ignored']" -v @path -n | xargs rm -rf</pre>

==[[~~Shell|~~bash]] interactions==

==[[bash]] interactions==

* [http://www.gnu.org/s/hello/manual/make/Choosing-the-Shell.html The shell to use] can be specified via $(SHELL). By default, <tt>/bin/sh</tt> is used

** Unlike most variables, it cannot be inherited from the environment (except on Windows, where it is)

Line 25:

* Arguments to the shell can be specified via <tt>.SHELLFLAGS</tt>

** By default, it's <tt>-c</tt>, or <tt>-ec</tt> in POSIX mode

* Remember that errors in the body of a shell loop don't set the overall return value!<~~code~~>

* Remember that errors in the body of a shell loop don't set the overall return value:

target:

<pre>target:

~~&+nbspwhile~~ true ; do false ; done</~~code~~>This recipe cannot be successfully completed!

while true ; do false ; done</pre>

This recipe cannot be successfully completed! You can use<pre>target:

set -e ; while true ; do false ; done</pre>or <pre>target:

while true ; do false || exit ; done</pre>

The former is probably nicer, since you can then use ; in the place of &&, but it deviates from expected gmake semantics. In general, you don't want to be doing this kind of thing anyway; it's useful for cases like running unit testing on a set of inputs, where outputs won't be generated.

GNU Make: Difference between revisions

Dank (talk | contribs)

@@ Line 19: / Line 19: @@
 ** If <tt>svn:ignore</tt> is properly used, the following rule suffices as a project-independent <tt>clean</tt> target, assuming the presence of [[xmlstarlet]]:<pre>svn --xml --no-ignore status | xmlstarlet sel -t -m //entry -i "wc-status[@item='ignored']" -v @path -n | xargs rm -rf</pre>
-==[[Shell|bash]] interactions==
+==[[bash]] interactions==
 * [http://www.gnu.org/s/hello/manual/make/Choosing-the-Shell.html The shell to use] can be specified via $(SHELL). By default, <tt>/bin/sh</tt> is used
 ** Unlike most variables, it cannot be inherited from the environment (except on Windows, where it is)
@@ Line 25: / Line 25: @@
 * Arguments to the shell can be specified via <tt>.SHELLFLAGS</tt>
 ** By default, it's <tt>-c</tt>, or <tt>-ec</tt> in POSIX mode
-* Remember that errors in the body of a shell loop don't set the overall return value!<code>
+* Remember that errors in the body of a shell loop don't set the overall return value:
-target:
+<pre>target:
-&+nbspwhile true ; do false ; done</code>This recipe cannot be successfully completed!
+        while true ; do false ; done</pre>
+This recipe cannot be successfully completed! You can use<pre>target:
+        set -e ; while true ; do false ; done</pre>or <pre>target:
+        while true ; do false || exit ; done</pre>
+The former is probably nicer, since you can then use ; in the place of &&, but it deviates from expected gmake semantics. In general, you don't want to be doing this kind of thing anyway; it's useful for cases like running unit testing on a set of inputs, where outputs won't be generated.