This provides some examples on using dpkg-buildflags and buildflags.mk in debian/rules, notes that --export=make is not recommended and explicitly mentions that the list of build flags is subject to change.
Closes: #657627 Signed-off-by: Matthijs Kooijman <[email protected]> --- man/dpkg-buildflags.1 | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) diff --git a/man/dpkg-buildflags.1 b/man/dpkg-buildflags.1 index ea61306..219dc78 100644 --- a/man/dpkg-buildflags.1 +++ b/man/dpkg-buildflags.1 @@ -91,6 +91,11 @@ command-line. If the \fIformat\fP value is not given, \fBsh\fP is assumed. Only compilation flags starting with an upper case character are included, others are assumed to not be suitable for the environment. + +Note that evaluating \fB--export=make\fP output from a Makefile does not +always work as expected, so it is recommended to use +\fBbuildflags.mk\fP instead (see the \fBDEBIAN/RULES\fP section +below). .TP .BI \-\-get " flag" Print the value of the flag on standard output. Exits with 0 @@ -161,6 +166,50 @@ objects (if the linker is called directly, then and .B , have to be stripped from these options). Default value: empty. +.P +New flags might be added in the future if the need arises (for example +to support other languages). +. +.SH DEBIAN/RULES +You should call \fBdpkg-buildflags\fP or include \fBbuildflags.mk\fP +from the \fBdebian/rules\fP file to obtain the needed build flags to +pass to the build system. +.P +Note that older versions of dpkg (before 1.16.1) exported these flags +automatically. However, you should not rely on this, since this breaks +manual invocation of \fBdebian/rules\fP. +.P +For autoconf based packages, you can pass the relevant options to +configure directly: +.P + ./configure $(shell dpkg-buildflags --export=configure) +.P +For other build systems, or when you need more fine-grained control +about which flags are passed where, you can include \fBbuildflags.mk\fP +instead, which takes care of calling \fBdpkg-buildflags\fP and storing +the build flags in make variables. +.P +If you want to export all buildflags into the environment (where they +can be picked up by your build system): +.P + DPKG_EXPORT_BUILDFLAGS = 1 + include /usr/share/dpkg/buildflags.mk +.P +For some extra control over what is exported, you can manually export +the variables: +.P + include /usr/share/dpkg/buildflags.mk + export CPPFLAGS CFLAGS LDFLAGS +.P +And you can of course pass the flags to commands manually: +.P + include /usr/share/dpkg/buildflags.mk + binary: + cc -o hello hello.c $(CFLAGS) $(LDFLAGS) +.P +When using the \fBbuildflags.mk\fP file, the package should Build-Depend +on dpkg-dev (>= 1.16.1). Alternatively, you can use \fB\-include\fP to +not fail when the file is missing. . .SH FILES .TP @@ -169,6 +218,10 @@ System wide configuration file. .TP .BR $XDG_CONFIG_HOME/dpkg/buildflags.conf " or " $HOME/.config/dpkg/buildflags.conf User configuration file. +.TP +.B /usr/share/dpkg/buildflags.mk +Makefile snippet that will load (and optionally export) all flags +supported by \fBdpkg-buildflags\fP into variables. .SH ENVIRONMENT There are 2 sets of environment variables doing the same operations, the first one (DEB_\fIflag\fP_\fIop\fP) should never be used within -- 1.8.0 -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected]
