From 754bbf7a25a8dda49b5d08ef0d0443bbf5af0e36 Mon Sep 17 00:00:00 2001 From: Craig Jennings Date: Sun, 7 Apr 2024 13:41:34 -0500 Subject: new repository --- devdocs/gnu_make/testing-flags.html | 14 ++++++++++++++ 1 file changed, 14 insertions(+) create mode 100644 devdocs/gnu_make/testing-flags.html (limited to 'devdocs/gnu_make/testing-flags.html') diff --git a/devdocs/gnu_make/testing-flags.html b/devdocs/gnu_make/testing-flags.html new file mode 100644 index 00000000..a87777df --- /dev/null +++ b/devdocs/gnu_make/testing-flags.html @@ -0,0 +1,14 @@ +

Conditionals that Test Flags

You can write a conditional that tests make command flags such as ‘-t’ by using the variable MAKEFLAGS together with the findstring function (see Functions for String Substitution and Analysis). This is useful when touch is not enough to make a file appear up to date.

Recall that MAKEFLAGS will put all single-letter options (such as ‘-t’) into the first word, and that word will be empty if no single-letter options were given. To work with this, it’s helpful to add a value at the start to ensure there’s a word: for example ‘-$(MAKEFLAGS)’.

The findstring function determines whether one string appears as a substring of another. If you want to test for the ‘-t’ flag, use ‘t’ as the first string and the first word of MAKEFLAGS as the other.

For example, here is how to arrange to use ‘ranlib -t’ to finish marking an archive file up to date: 

archive.a: …
+ifneq (,$(findstring t,$(word 1,-$(MAKEFLAGS))))
+        +touch archive.a
+        +ranlib -t archive.a
+else
+        ranlib archive.a
+endif
+
+

The ‘+’ prefix marks those recipe lines as “recursive” so that they will be executed despite use of the ‘-t’ flag. See Recursive Use of make.

+

+ 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.
Licensed under the GNU Free Documentation License.
+ https://www.gnu.org/software/make/manual/html_node/Testing-Flags.html +

+
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