d95d61b1af
* Better refcounting Cribbed from [Rust Arc][1] and the [Boost docs][2]: """ Increasing the reference counter can always be done with memory_order_relaxed: New references to an object can only be formed from an existing reference, and passing an existing reference from one thread to another must already provide any required synchronization. It is important to enforce any possible access to the object in one thread (through an existing reference) to happen before deleting the object in a different thread. This is achieved by a "release" operation after dropping a reference (any access to the object through this reference must obviously happened before), and an "acquire" operation before deleting the object. It would be possible to use memory_order_acq_rel for the fetch_sub operation, but this results in unneeded "acquire" operations when the reference counter does not yet reach zero and may impose a performance penalty. """ [1] https://moshg.github.io/rust-std-ja/src/alloc/arc.rs.html [2] https://www.boost.org/doc/libs/1_55_0/doc/html/atomic/usage_examples.html * Make ZiposHandle's pos atomic Implements a somewhat stronger guarantee than POSIX specifies: reads and seeks are atomic. They may be arbitrarily reordered between threads, but each one happens all the way and leaves the fd in a consistent state. This is achieved by "locking" pos in __zipos_read by storing SIZE_MAX to pos during the operation, so only one can be in-flight at a time. Seeks, on the other hand, just update pos in one go, and rerun if it changed in the meantime. I used `LIKELY` / `UNLIKELY` to pessimize the concurrent case; hopefully that buys back some performance. |
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| .. | ||
| calls | ||
| crt | ||
| dlopen | ||
| dns | ||
| elf | ||
| fmt | ||
| integral | ||
| intrin | ||
| irq | ||
| isystem | ||
| log | ||
| mem | ||
| nexgen32e | ||
| nt | ||
| proc | ||
| runtime | ||
| sock | ||
| stdio | ||
| str | ||
| sysv | ||
| testlib | ||
| thread | ||
| time | ||
| tinymath | ||
| vga | ||
| x | ||
| ar.h | ||
| assert.h | ||
| atomic.h | ||
| BUILD.mk | ||
| complex.h | ||
| cosmo.h | ||
| cxxabi.h | ||
| dce.h | ||
| disclaimer.inc | ||
| dos.internal.h | ||
| empty.s | ||
| errno.h | ||
| imag.internal.h | ||
| inttypes.h | ||
| iso646.internal.h | ||
| limits.h | ||
| literal.h | ||
| mach.internal.h | ||
| macho.internal.h | ||
| macros.internal.h | ||
| math.h | ||
| notice.inc | ||
| notice.internal.h | ||
| paths.h | ||
| README.md | ||
| serialize.h | ||
| stdalign.internal.h | ||
| stdbool.h | ||
| stdckdint.h | ||
| stdlib.h | ||
| temp.h | ||
| testlib-test.txt | ||
| type2str.h | ||
| zip.internal.h | ||
Cosmopolitan Standard Library
This directory defines static archives defining functions, like
printf(), mmap(), win32, etc. Please note that the Cosmopolitan
build configuration doesn't link any C/C++ library dependencies
by default, so you still have the flexibility to choose the one
provided by your system. If you'd prefer Cosmopolitan, just add
$(LIBC) and $(CRT) to your linker arguments.
Your library is compromised of many bite-sized static archives. We use the checkdeps tool to guarantee that the contents of the archives are organized in a logical way that's easy to use with or without our makefile infrastructure, since there's no cyclic dependencies.
The Cosmopolitan Library exports only the most stable canonical
system calls for all supported operating systems, regardless of
which platform is used for compilation. We polyfill many of the
APIs, e.g. read(), write() so they work consistently everywhere
while other apis, e.g. CreateWindowEx(), might only work on one
platform, in which case they become no-op functions on others.
Cosmopolitan polyfill wrappers will usually use the dollar sign naming convention, so they may be bypassed when necessary. This same convention is used when multiple implementations of string library and other performance-critical function are provided to allow Cosmopolitan to go fast on both old and newer computers.
We take an approach to configuration that relies heavily on the
compiler's dead code elimination pass (libc/dce.h). Most of the
code is written so that, for example, folks not wanting support
for OpenBSD can flip a bit in SUPPORT_VECTOR and that code will
be omitted from the build. The same is true for builds that are
tuned using -march=native which effectively asks the library to
not include runtime support hooks for x86 processors older than
what you use.
Please note that, unlike Cygwin or MinGW, Cosmopolitan does not achieve broad support by bolting on a POSIX emulation layer. We do nothing more than (in most cases) stateless API translations that get you 90% of the way there in a fast lightweight manner. We therefore can't address some of the subtle differences, such as the nuances of absolute paths on Windows. Our approach could be compared to something more along the lines of, "the Russians just used a pencil to write in space", versus spending millions researching a pen like NASA.