#ifndef VLIBC_POLL_H
#define VLIBC_POLL_H

/*
 * vlibc — <poll.h>.
 *
 * Poll multiple file descriptors for readiness. Every declaration here is a
 * thin pass-through to the kernel: poll() blocks per its millisecond
 * timeout, ppoll() takes a struct timespec and an optional signal mask
 * directly, and both return the count of ready descriptors (0 on timeout,
 * -1 with errno set on error).
 *
 *   Level 1 (onlyposix): poll, nfds_t, struct pollfd, the POLL* event bits.
 *   Level 2 (muslmimic): ppoll (Linux-specific; POSIX has only poll).
 *
 * struct pollfd and the POLL* values mirror the kernel ABI (x86_64
 * asm-generic/poll.h) exactly: the wrappers pass them to SYS_ppoll
 * unmodified. POLLERR, POLLHUP and POLLNVAL are report-only — they can
 * appear in revents even when not requested in events.
 *
 * The signal mask type ppoll takes is declared under the shared guard
 * below; <signal.h> is its canonical POSIX home and will own the full sig*
 * API.
 */

#include <vlibc/features.h>

#include <sys/types.h>

#include <time.h>

#ifdef __cplusplus
extern "C" {
#endif

/* Requestable event bits (poll()'s events field). */
#define POLLIN 0x001  /* readable */
#define POLLPRI 0x002 /* urgent readable (out-of-band) */
#define POLLOUT 0x004 /* writable */

/* Report-only event bits (poll()'s revents field). */
#define POLLERR 0x008  /* error condition */
#define POLLHUP 0x010  /* hung up */
#define POLLNVAL 0x020 /* invalid fd */

/* The number of struct pollfd entries poll()/ppoll() watch. */
typedef unsigned long nfds_t;

/*
 * One descriptor watched by poll()/ppoll(). fd is the descriptor (negative
 * to ignore), events the requested bits (POLLIN/POLLOUT), revents the bits
 * the kernel reports (the requested bits plus any POLLERR/POLLHUP/POLLNVAL).
 */
struct pollfd
{
    int fd;
    short events;
    short revents;
};

/*
 * Wait for readiness on the first nfds entries of fds, blocking up to
 * timeout milliseconds (timeout < 0 blocks indefinitely, 0 never blocks).
 * Return the number of entries with a nonzero revents, 0 on timeout, or -1
 * with errno set on error.
 */
int
poll(struct pollfd *fds, nfds_t nfds, int timeout);

#if VLIBC_LEVEL_GE(2)
/* Level 2 (muslmimic): Linux-specific. */

#ifndef VLIBC_SIGSET_T_DEFINED
#define VLIBC_SIGSET_T_DEFINED
/*
 * Signal mask type: a single 64-bit word — the x86_64 Linux sigset_t (see
 * setjmp.h). <signal.h> is the canonical POSIX home for sigset_t and builds
 * the sig* API on this same layout; the typedef is repeated in
 * <sys/select.h> under this guard so the two headers stay consistent.
 */
typedef unsigned long sigset_t;
#endif

/*
 * Like poll(), but the timeout is a struct timespec and, when sigmask is
 * not NULL, the given signal mask is atomically installed for the duration
 * of the wait (the previous mask is restored before returning).
 * Linux-specific.
 */
int
ppoll(struct pollfd *fds, nfds_t nfds, const struct timespec *timeout, const sigset_t *sigmask);

#endif /* VLIBC_LEVEL_GE(2) */

#ifdef __cplusplus
}
#endif

#endif /* VLIBC_POLL_H */