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Diffstat (limited to 'include/ruby/internal/intern/select.h')
| -rw-r--r-- | include/ruby/internal/intern/select.h | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/include/ruby/internal/intern/select.h b/include/ruby/internal/intern/select.h new file mode 100644 index 0000000000..ba75213618 --- /dev/null +++ b/include/ruby/internal/intern/select.h @@ -0,0 +1,88 @@ +#ifndef RBIMPL_INTERN_SELECT_H /*-*-C++-*-vi:se ft=cpp:*/ +#define RBIMPL_INTERN_SELECT_H +/** + * @file + * @author Ruby developers <ruby-core@ruby-lang.org> + * @copyright This file is a part of the programming language Ruby. + * Permission is hereby granted, to either redistribute and/or + * modify this file, provided that the conditions mentioned in the + * file COPYING are met. Consult the file for details. + * @warning Symbols prefixed with either `RBIMPL` or `rbimpl` are + * implementation details. Don't take them as canon. They could + * rapidly appear then vanish. The name (path) of this header file + * is also an implementation detail. Do not expect it to persist + * at the place it is now. Developers are free to move it anywhere + * anytime at will. + * @note To ruby-core: remember that this header can be possibly + * recursively included from extension libraries written in C++. + * Do not expect for instance `__VA_ARGS__` is always available. + * We assume C99 for ruby itself but we don't assume languages of + * extension libraries. They could be written in C++98. + * @brief Public APIs to provide ::rb_fd_select(). + * @note Functions and structs defined in this header file are not + * necessarily ruby-specific. They don't need ::VALUE etc. + */ +#include "ruby/internal/config.h" + +#ifdef HAVE_SYS_TYPES_H +# include <sys/types.h> /* for NFDBITS (BSD Net/2) */ +#endif + +#include "ruby/internal/dllexport.h" + +/* thread.c */ +#if defined(NFDBITS) && defined(HAVE_RB_FD_INIT) +# include "ruby/internal/intern/select/largesize.h" +#elif defined(_WIN32) +# include "ruby/internal/intern/select/win32.h" +# /** Does nothing (defined for compatibility). */ +# define rb_fd_resize(n, f) ((void)(f)) +#else +# include "ruby/internal/intern/select/posix.h" +# /** Does nothing (defined for compatibility). */ +# define rb_fd_resize(n, f) ((void)(f)) +#endif + +RBIMPL_SYMBOL_EXPORT_BEGIN() + +struct timeval; + +/** + * Waits for multiple file descriptors at once. This is basically a wrapper of + * system-provided select() with releasing GVL, to allow other Ruby threads run + * in parallel. + * + * @param[in] nfds Max FD in everything passed, plus one. + * @param[in,out] rfds Set of FDs to wait for reads. + * @param[in,out] wfds Set of FDs to wait for writes. + * @param[in,out] efds Set of FDs to wait for OOBs. + * @param[in,out] timeout Max blocking duration. + * @retval -1 Failed, errno set. + * @retval 0 Timeout exceeded. + * @retval otherwise Total number of file descriptors returned. + * @post `rfds` contains readable FDs. + * @post `wfds` contains writable FDs. + * @post `efds` contains exceptional FDs. + * @post `timeout` is the time left. + * @note All pointers are allowed to be null pointers. + * + * Although backend threads can run in parallel of this function, touching a + * file descriptor from multiple threads could be problematic. For instance + * what happens when a thread closes a file descriptor that is selected by + * someone else, vastly varies among operating systems. You would better avoid + * touching an fd from more than one threads. + * + * NOTE: this function is used in native extensions, so change its API with care. + * + * @internal + * + * Although any file descriptors are possible here, it makes completely no + * sense to pass a descriptor that is not `O_NONBLOCK`. If you want to know + * the reason for this limitation in detail, you might find this thread super + * interesting: https://lkml.org/lkml/2004/10/6/117 + */ +int rb_thread_fd_select(int nfds, rb_fdset_t *rfds, rb_fdset_t *wfds, rb_fdset_t *efds, struct timeval *timeout); + +RBIMPL_SYMBOL_EXPORT_END() + +#endif /* RBIMPL_INTERN_SELECT_H */ |