Welcome to Bionic, Android's small and custom C library for the Android platform. Bionic is mainly a port of the BSD C library to our Linux kernel with the following additions/changes: - no support for locales - no support for wide chars (i.e. multi-byte characters) - its own smallish implementation of pthreads based on Linux futexes - support for x86, ARM and ARM thumb CPU instruction sets and kernel interfaces Bionic is released under the standard 3-clause BSD License Bionic doesn't want to implement all features of a traditional C library, we only add features to it as we need them, and we try to keep things as simple and small as possible. Our goal is not to support scaling to thousands of concurrent threads on multi-processors machines; we're running this on cell-phones, damnit !! Note that Bionic doesn't provide a libthread_db or a libm implementation. Adding new syscalls: ==================== Bionic provides the gensyscalls.py Python script to automatically generate syscall stubs from the list defined in the file SYSCALLS.TXT. You can thus add a new syscall by doing the following: - edit SYSCALLS.TXT - add a new line describing your syscall, it should look like: return_type syscall_name(parameters) syscall_number - in the event where you want to differentiate the syscall function from its entry name, use the alternate: return_type funcname:syscall_name(parameters) syscall_number - additionally, if the syscall number is different between ARM and x86, use: return_type funcname[:syscall_name](parameters) arm_number,x86_number - a syscall number can be -1 to indicate that the syscall is not implemented on a given platform, for example: void __set_tls(void*) arm_number,-1 the comments in SYSCALLS.TXT contain more information about the line format You can also use the 'checksyscalls.py' script to check that all the syscall numbers you entered are correct. It does so by looking at the values defined in your Linux kernel headers. The script indicates where the values are incorrect and what is expected instead.