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| author | Craig Jennings <c@cjennings.net> | 2024-04-07 13:41:34 -0500 |
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| committer | Craig Jennings <c@cjennings.net> | 2024-04-07 13:41:34 -0500 |
| commit | 754bbf7a25a8dda49b5d08ef0d0443bbf5af0e36 (patch) | |
| tree | f1190704f78f04a2b0b4c977d20fe96a828377f1 /devdocs/gnu_make/variables-in-recipes.html | |
new repository
Diffstat (limited to 'devdocs/gnu_make/variables-in-recipes.html')
| -rw-r--r-- | devdocs/gnu_make/variables-in-recipes.html | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/devdocs/gnu_make/variables-in-recipes.html b/devdocs/gnu_make/variables-in-recipes.html new file mode 100644 index 00000000..00d1d05b --- /dev/null +++ b/devdocs/gnu_make/variables-in-recipes.html @@ -0,0 +1,20 @@ + <h1 class="subsection">Using Variables in Recipes</h1> <p>The other way in which <code>make</code> processes recipes is by expanding any variable references in them (see <a href="reference">Basics of Variable References</a>). This occurs after make has finished reading all the makefiles and the target is determined to be out of date; so, the recipes for targets which are not rebuilt are never expanded. </p> <p>Variable and function references in recipes have identical syntax and semantics to references elsewhere in the makefile. They also have the same quoting rules: if you want a dollar sign to appear in your recipe, you must double it (‘<samp>$$</samp>’). For shells like the default shell, that use dollar signs to introduce variables, it’s important to keep clear in your mind whether the variable you want to reference is a <code>make</code> variable (use a single dollar sign) or a shell variable (use two dollar signs). For example: </p> <div class="example"> <pre class="example">LIST = one two three +all: + for i in $(LIST); do \ + echo $$i; \ + done +</pre> +</div> <p>results in the following command being passed to the shell: </p> <div class="example"> <pre class="example">for i in one two three; do \ + echo $i; \ +done +</pre> +</div> <p>which generates the expected result: </p> <div class="example"> <pre class="example">one +two +three +</pre> +</div><div class="_attribution"> + <p class="_attribution-p"> + Copyright © 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022 Free Software Foundation, Inc. <br>Licensed under the GNU Free Documentation License.<br> + <a href="https://www.gnu.org/software/make/manual/html_node/Variables-in-Recipes.html" class="_attribution-link">https://www.gnu.org/software/make/manual/html_node/Variables-in-Recipes.html</a> + </p> +</div> |