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path: root/src/unistd/pause.c
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2014-05-29support linux kernel apis (new archs) with old syscalls removedRich Felker1-0/+5
such archs are expected to omit definitions of the SYS_* macros for syscalls their kernels lack from arch/$ARCH/bits/syscall.h. the preprocessor is then able to select the an appropriate implementation for affected functions. two basic strategies are used on a case-by-case basis: where the old syscalls correspond to deprecated library-level functions, the deprecated functions have been converted to wrappers for the modern function, and the modern function has fallback code (omitted at the preprocessor level on new archs) to make use of the old syscalls if the new syscall fails with ENOSYS. this also improves functionality on older kernels and eliminates the incentive to program with deprecated library-level functions for the sake of compatibility with older kernels. in other situations where the old syscalls correspond to library-level functions which are not deprecated but merely lack some new features, such as the *at functions, the old syscalls are still used on archs which support them. this may change at some point in the future if or when fallback code is added to the new functions to make them usable (possibly with reduced functionality) on old kernels.
2011-04-17overhaul pthread cancellationRich Felker1-5/+1
this patch improves the correctness, simplicity, and size of cancellation-related code. modulo any small errors, it should now be completely conformant, safe, and resource-leak free. the notion of entering and exiting cancellation-point context has been completely eliminated and replaced with alternative syscall assembly code for cancellable syscalls. the assembly is responsible for setting up execution context information (stack pointer and address of the syscall instruction) which the cancellation signal handler can use to determine whether the interrupted code was in a cancellable state. these changes eliminate race conditions in the previous generation of cancellation handling code (whereby a cancellation request received just prior to the syscall would not be processed, leaving the syscall to block, potentially indefinitely), and remedy an issue where non-cancellable syscalls made from signal handlers became cancellable if the signal handler interrupted a cancellation point. x86_64 asm is untested and may need a second try to get it right.
2011-03-20global cleanup to use the new syscall interfaceRich Felker1-1/+1
2011-02-12initial check-in, version 0.5.0v0.5.0Rich Felker1-0/+12