I don't know all that much about it. Mostly it just seems to work. I'm quoting from: https://en.wikipedia.org/wiki/Bionic_(software) ;-) Bionic is basically a BSD licensed C library for use with Linux. This differs from other BSD C libraries which require a BSD kernel, and from the GNU C Library (glibc) which uses the GNU Lesser General Public License. For the most part it's supposed to be drop-in compatible I think, and the kernel headers (uapi) come from some recent version of Linux. The license and smaller size are AFAIK the main benefits. --- Got me curious and: I'm not actually sure what defines __ANDROID__, maybe __BIONIC__ would be a better guard? That seems to be defined in bionic/libc/include/sys/cdefs.h https://android.googlesource.com/platform/bionic/+/master/libc/include/sys/cdefs.h#43 And the docs here: https://android.googlesource.com/platform/bionic/+/master/docs/defines.md do seem to suggest that __BIONIC__ is more equivalent to __GLIBC__
