This is what GCC manual says [1]: -------------------------->8---------------------- --enable-__cxa_atexit Define if you want to use __cxa_atexit, rather than atexit, to register C++ destructors for local statics and global objects. This is essential for fully standards-compliant handling of destructors, but requires __cxa_atexit in libc. This option is currently only available on systems with GNU libc ... -------------------------->8---------------------- Important disadvantages of a simple atexit() are that [2]: -------------------------->8---------------------- 1999 C Standard only requires that the implementation support 32 registered functions, although most implementations support many more. More important it does not deal at all with the ability in most implementations to remove DSOs from a running program image by calling dlclose prior to program termination. -------------------------->8---------------------- Also it seems like all libc's we support in Buildroot (Glibc, uClibc and musl) support __cxa_at_exit() so enable it unconditionally. FWIW if we look around we'll see: 1. In OpenEmbedded it is enabled for everything except gcc-cross-initial: [3], [4] 2. In Crosstool-NG it is enabled by default: [5] 3. In OpenWrt it is disabled only for uClibc, otherwise enabled: [6] So I think we should be good with it as well. [1] https://gcc.gnu.org/install/configure.html [2] https://itanium-cxx-abi.github.io/cxx-abi/abi.html#dso-dtor-motivation [3] https://github.com/openembedded/openembedded-core/blob/master/meta/recipes-devtools/gcc/gcc-configure-common.inc#L59 [4] https://github.com/openembedded/openembedded-core/blob/master/meta/recipes-devtools/gcc/gcc-cross-initial.inc#L23 [5] https://github.com/crosstool-ng/crosstool-ng/blob/master/config/cc/gcc.in#L270 [6] https://github.com/openwrt/openwrt/blob/master/toolchain/gcc/common.mk#L170 Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com> Cc: Nicolas Cavallari <Nicolas.Cavallari@green-communications.fr> Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com> Cc: Mark Corbin <mark.corbin@embecosm.com> Cc: Romain Naour <romain.naour@gmail.com> Cc: Peter Korsgaard <peter@korsgaard.com> Cc: Bernd Kuhls <bernd.kuhls@t-online.de> Cc: Claudiu Zissulescu <claziss@synopsys.com> Cc: Cupertino Miranda <cmiranda@synopsys.com> Cc: Vineet Gupta <vgupta@synopsys.com> Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com> |
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arch | ||
board | ||
boot | ||
configs | ||
docs | ||
fs | ||
linux | ||
package | ||
support | ||
system | ||
toolchain | ||
utils | ||
.defconfig | ||
.flake8 | ||
.gitignore | ||
.gitlab-ci.yml | ||
.gitlab-ci.yml.in | ||
CHANGES | ||
Config.in | ||
Config.in.legacy | ||
COPYING | ||
DEVELOPERS | ||
Makefile | ||
Makefile.legacy | ||
README |
Buildroot is a simple, efficient and easy-to-use tool to generate embedded Linux systems through cross-compilation. The documentation can be found in docs/manual. You can generate a text document with 'make manual-text' and read output/docs/manual/manual.text. Online documentation can be found at http://buildroot.org/docs.html To build and use the buildroot stuff, do the following: 1) run 'make menuconfig' 2) select the target architecture and the packages you wish to compile 3) run 'make' 4) wait while it compiles 5) find the kernel, bootloader, root filesystem, etc. in output/images You do not need to be root to build or run buildroot. Have fun! Buildroot comes with a basic configuration for a number of boards. Run 'make list-defconfigs' to view the list of provided configurations. Please feed suggestions, bug reports, insults, and bribes back to the buildroot mailing list: buildroot@buildroot.org You can also find us on #buildroot on Freenode IRC. If you would like to contribute patches, please read https://buildroot.org/manual.html#submitting-patches