What are the most important POSIX functions not available in Android?

Question

I\'m about to port a large C++ project (some sort of Library Project, it contains absolutely no GUI) to Android. It\'s actually a Visual C++ project, but it will be ported t

Answer 1

Bionic Wikipedia page

https://en.wikipedia.org/wiki/Bionic_(software)#Differences_from_POSIX

Also has some interesting info:

Although bionic aims to implement all of C11 and POSIX, there are still (as of Oreo) about 70 POSIX functions missing[8] from libc. There are also POSIX functions such as the endpwent/getpwent/setpwent family that are inapplicable to Android because it lacks a passwd database. As of Oreo, libm is complete.

Some functions deliberately do not conform to the POSIX or C standards for security reasons, such as printf which does not support the %n format string.[9]

Official Bionic in tree documentation quote

https://android.googlesource.com/platform/bionic/+/37ad9597839c70a7ec79578e5072df9c189fc830/docs/status.md

Run ./libc/tools/check-symbols-glibc.py in bionic/ for the current list of POSIX functions implemented by glibc but not by bionic. Currently (2017-10):

aio_cancel
aio_error
aio_fsync
aio_read
aio_return
aio_suspend
aio_write
lio_listio
pthread_cancel
pthread_mutex_consistent
pthread_mutex_getprioceiling
pthread_mutex_setprioceiling
pthread_mutexattr_getprioceiling
pthread_mutexattr_getprotocol
pthread_mutexattr_getrobust
pthread_mutexattr_setprioceiling
pthread_mutexattr_setprotocol
pthread_mutexattr_setrobust
pthread_setcancelstate
pthread_setcanceltype
pthread_testcancel
wordexp
wordfree
libm

Current libm symbols: https://android.googlesource.com/platform/bionic/+/master/libm/libm.map.txt

0 remaining missing POSIX libm functions.