//! Definitions found commonly among almost all Unix derivatives
//!
//! More functions and definitions can be found in the more specific modules
//! according to the platform in question.

pub type pid_t = i32;
pub type uid_t = u32;
pub type gid_t = u32;
pub type in_addr_t = u32;
pub type in_port_t = u16;
pub type sighandler_t = ::size_t;
pub type cc_t = ::c_uchar;

pub enum DIR {}

s! {
    pub struct utimbuf {
        pub actime: time_t,
        pub modtime: time_t,
    }

    pub struct timeval {
        pub tv_sec: time_t,
        pub tv_usec: suseconds_t,
    }

    pub struct timespec {
        pub tv_sec: time_t,
        pub tv_nsec: c_long,
    }

    pub struct rlimit {
        pub rlim_cur: rlim_t,
        pub rlim_max: rlim_t,
    }

    pub struct rusage {
        pub ru_utime: timeval,
        pub ru_stime: timeval,
        pub ru_maxrss: c_long,
        pub ru_ixrss: c_long,
        pub ru_idrss: c_long,
        pub ru_isrss: c_long,
        pub ru_minflt: c_long,
        pub ru_majflt: c_long,
        pub ru_nswap: c_long,
        pub ru_inblock: c_long,
        pub ru_oublock: c_long,
        pub ru_msgsnd: c_long,
        pub ru_msgrcv: c_long,
        pub ru_nsignals: c_long,
        pub ru_nvcsw: c_long,
        pub ru_nivcsw: c_long,

        #[cfg(target_env = "musl")]
        __reserved: [c_long; 16],
    }

    #[cfg_attr(target_os = "netbsd", repr(packed))]
    pub struct in_addr {
        pub s_addr: in_addr_t,
    }

    pub struct in6_addr {
        pub s6_addr: [u8; 16],
        __align: [u32; 0],
    }

    pub struct ip_mreq {
        pub imr_multiaddr: in_addr,
        pub imr_interface: in_addr,
    }

    pub struct ipv6_mreq {
        pub ipv6mr_multiaddr: in6_addr,
        #[cfg(target_os = "android")]
        pub ipv6mr_interface: ::c_int,
        #[cfg(not(target_os = "android"))]
        pub ipv6mr_interface: ::c_uint,
    }

    pub struct hostent {
        pub h_name: *mut ::c_char,
        pub h_aliases: *mut *mut ::c_char,
        pub h_addrtype: ::c_int,
        pub h_length: ::c_int,
        pub h_addr_list: *mut *mut ::c_char,
    }

    pub struct iovec {
        pub iov_base: *mut ::c_void,
        pub iov_len: ::size_t,
    }
}

pub const WNOHANG: ::c_int = 1;
pub const SIG_DFL: sighandler_t = 0 as sighandler_t;
pub const SIG_IGN: sighandler_t = 1 as sighandler_t;
pub const SIG_ERR: sighandler_t = !0 as sighandler_t;

pub const DT_FIFO: u8 = 1;
pub const DT_CHR: u8 = 2;
pub const DT_DIR: u8 = 4;
pub const DT_BLK: u8 = 6;
pub const DT_REG: u8 = 8;
pub const DT_LNK: u8 = 10;
pub const DT_SOCK: u8 = 12;

pub const FD_CLOEXEC: ::c_int = 0x1;

pub const USRQUOTA: ::c_int = 0;
pub const GRPQUOTA: ::c_int = 1;

pub const SIGIOT: ::c_int = 6;

pub const S_ISUID: ::c_int = 0x800;
pub const S_ISGID: ::c_int = 0x400;
pub const S_ISVTX: ::c_int = 0x200;

cfg_if! {
    if #[cfg(feature = "default")] {
        // cargo build, don't pull in anything extra as the libstd  dep
        // already pulls in all libs.
    } else if #[cfg(target_env = "musl")] {
        #[link(name = "c", kind = "static")]
        extern {}
    } else if #[cfg(any(target_os = "macos",
                        target_os = "ios",
                        target_os = "android",
                        target_os = "openbsd",
                        target_os = "bitrig"))] {
        #[link(name = "c")]
        #[link(name = "m")]
        extern {}
    } else {
        #[link(name = "c")]
        #[link(name = "m")]
        #[link(name = "rt")]
        extern {}
    }
}

extern {
    #[cfg_attr(target_os = "netbsd", link_name = "__socket30")]
    pub fn socket(domain: ::c_int, ty: ::c_int, protocol: ::c_int) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "connect$UNIX2003")]
    pub fn connect(socket: ::c_int, address: *const sockaddr,
                   len: socklen_t) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "bind$UNIX2003")]
    pub fn bind(socket: ::c_int, address: *const sockaddr,
                address_len: socklen_t) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "listen$UNIX2003")]
    pub fn listen(socket: ::c_int, backlog: ::c_int) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "accept$UNIX2003")]
    pub fn accept(socket: ::c_int, address: *mut sockaddr,
                  address_len: *mut socklen_t) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "getpeername$UNIX2003")]
    pub fn getpeername(socket: ::c_int, address: *mut sockaddr,
                       address_len: *mut socklen_t) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "getsockname$UNIX2003")]
    pub fn getsockname(socket: ::c_int, address: *mut sockaddr,
                       address_len: *mut socklen_t) -> ::c_int;
    pub fn setsockopt(socket: ::c_int, level: ::c_int, name: ::c_int,
                      value: *const ::c_void,
                      option_len: socklen_t) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "socketpair$UNIX2003")]
    pub fn socketpair(domain: ::c_int, type_: ::c_int, protocol: ::c_int,
                      socket_vector: *mut ::c_int) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "sendto$UNIX2003")]
    pub fn sendto(socket: ::c_int, buf: *const ::c_void, len: ::size_t,
                  flags: ::c_int, addr: *const sockaddr,
                  addrlen: socklen_t) -> ::ssize_t;
    pub fn shutdown(socket: ::c_int, how: ::c_int) -> ::c_int;

    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "chmod$UNIX2003")]
    pub fn chmod(path: *const c_char, mode: mode_t) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "fchmod$UNIX2003")]
    pub fn fchmod(fd: ::c_int, mode: mode_t) -> ::c_int;

    #[cfg_attr(target_os = "macos", link_name = "fstat$INODE64")]
    #[cfg_attr(target_os = "netbsd", link_name = "__fstat50")]
    pub fn fstat(fildes: ::c_int, buf: *mut stat) -> ::c_int;

    pub fn mkdir(path: *const c_char, mode: mode_t) -> ::c_int;

    #[cfg_attr(target_os = "macos", link_name = "stat$INODE64")]
    #[cfg_attr(target_os = "netbsd", link_name = "__stat50")]
    pub fn stat(path: *const c_char, buf: *mut stat) -> ::c_int;

    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "popen$UNIX2003")]
    pub fn popen(command: *const c_char,
                 mode: *const c_char) -> *mut ::FILE;
    pub fn pclose(stream: *mut ::FILE) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "fdopen$UNIX2003")]
    pub fn fdopen(fd: ::c_int, mode: *const c_char) -> *mut ::FILE;
    pub fn fileno(stream: *mut ::FILE) -> ::c_int;

    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "open$UNIX2003")]
    pub fn open(path: *const c_char, oflag: ::c_int, ...) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "creat$UNIX2003")]
    pub fn creat(path: *const c_char, mode: mode_t) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "fcntl$UNIX2003")]
    pub fn fcntl(fd: ::c_int, cmd: ::c_int, ...) -> ::c_int;

    #[cfg_attr(all(target_os = "macos", target_arch = "x86_64"),
               link_name = "opendir$INODE64")]
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "opendir$INODE64$UNIX2003")]
    #[cfg_attr(target_os = "netbsd", link_name = "__opendir30")]
    pub fn opendir(dirname: *const c_char) -> *mut ::DIR;
    #[cfg_attr(target_os = "macos", link_name = "readdir_r$INODE64")]
    #[cfg_attr(target_os = "netbsd", link_name = "__readdir_r30")]
    pub fn readdir_r(dirp: *mut ::DIR, entry: *mut ::dirent,
                     result: *mut *mut ::dirent) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "closedir$UNIX2003")]
    pub fn closedir(dirp: *mut ::DIR) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86_64"),
               link_name = "rewinddir$INODE64")]
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "rewinddir$INODE64$UNIX2003")]
    pub fn rewinddir(dirp: *mut ::DIR);

    pub fn access(path: *const c_char, amode: ::c_int) -> ::c_int;
    pub fn alarm(seconds: ::c_uint) -> ::c_uint;
    pub fn chdir(dir: *const c_char) -> ::c_int;
    pub fn chown(path: *const c_char, uid: uid_t,
                 gid: gid_t) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "close$UNIX2003")]
    pub fn close(fd: ::c_int) -> ::c_int;
    pub fn dup(fd: ::c_int) -> ::c_int;
    pub fn dup2(src: ::c_int, dst: ::c_int) -> ::c_int;
    pub fn execv(prog: *const c_char,
                 argv: *const *const c_char) -> ::c_int;
    pub fn execve(prog: *const c_char, argv: *const *const c_char,
                  envp: *const *const c_char)
                  -> ::c_int;
    pub fn execvp(c: *const c_char,
                  argv: *const *const c_char) -> ::c_int;
    pub fn fork() -> pid_t;
    pub fn fpathconf(filedes: ::c_int, name: ::c_int) -> c_long;
    pub fn getcwd(buf: *mut c_char, size: ::size_t) -> *mut c_char;
    pub fn getegid() -> gid_t;
    pub fn geteuid() -> uid_t;
    pub fn getgid() -> gid_t;
    pub fn getgroups(ngroups_max: ::c_int, groups: *mut gid_t)
                     -> ::c_int;
    pub fn getlogin() -> *mut c_char;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "getopt$UNIX2003")]
    pub fn getopt(argc: ::c_int, argv: *const *mut c_char,
                  optstr: *const c_char) -> ::c_int;
    pub fn getpgrp() -> pid_t;
    pub fn getpid() -> pid_t;
    pub fn getppid() -> pid_t;
    pub fn getuid() -> uid_t;
    pub fn isatty(fd: ::c_int) -> ::c_int;
    pub fn link(src: *const c_char, dst: *const c_char) -> ::c_int;
    pub fn lseek(fd: ::c_int, offset: off_t, whence: ::c_int) -> off_t;
    pub fn pathconf(path: *const c_char, name: ::c_int) -> c_long;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "pause$UNIX2003")]
    pub fn pause() -> ::c_int;
    pub fn pipe(fds: *mut ::c_int) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "read$UNIX2003")]
    pub fn read(fd: ::c_int, buf: *mut ::c_void, count: ::size_t)
                -> ::ssize_t;
    pub fn rmdir(path: *const c_char) -> ::c_int;
    pub fn setgid(gid: gid_t) -> ::c_int;
    pub fn setpgid(pid: pid_t, pgid: pid_t) -> ::c_int;
    pub fn setsid() -> pid_t;
    pub fn setuid(uid: uid_t) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "sleep$UNIX2003")]
    pub fn sleep(secs: ::c_uint) -> ::c_uint;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "nanosleep$UNIX2003")]
    #[cfg_attr(target_os = "netbsd", link_name = "__nanosleep50")]
    pub fn nanosleep(rqtp: *const timespec,
                     rmtp: *mut timespec) -> ::c_int;
    pub fn tcgetpgrp(fd: ::c_int) -> pid_t;
    pub fn ttyname(fd: ::c_int) -> *mut c_char;
    pub fn unlink(c: *const c_char) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "wait$UNIX2003")]
    pub fn wait(status: *mut ::c_int) -> pid_t;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "waitpid$UNIX2003")]
    pub fn waitpid(pid: pid_t, status: *mut ::c_int, options: ::c_int)
                   -> pid_t;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "write$UNIX2003")]
    pub fn write(fd: ::c_int, buf: *const ::c_void, count: ::size_t)
                 -> ::ssize_t;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "pread$UNIX2003")]
    pub fn pread(fd: ::c_int, buf: *mut ::c_void, count: ::size_t,
                 offset: off_t) -> ::ssize_t;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "pwrite$UNIX2003")]
    pub fn pwrite(fd: ::c_int, buf: *const ::c_void, count: ::size_t,
                  offset: off_t) -> ::ssize_t;
    pub fn umask(mask: mode_t) -> mode_t;

    #[cfg_attr(target_os = "netbsd", link_name = "__utime50")]
    pub fn utime(file: *const c_char, buf: *const utimbuf) -> ::c_int;

    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
                   link_name = "kill$UNIX2003")]
    pub fn kill(pid: pid_t, sig: ::c_int) -> ::c_int;

    pub fn mlock(addr: *const ::c_void, len: ::size_t) -> ::c_int;
    pub fn munlock(addr: *const ::c_void, len: ::size_t) -> ::c_int;
    pub fn mlockall(flags: ::c_int) -> ::c_int;
    pub fn munlockall() -> ::c_int;

    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "mmap$UNIX2003")]
    pub fn mmap(addr: *mut ::c_void,
                len: ::size_t,
                prot: ::c_int,
                flags: ::c_int,
                fd: ::c_int,
                offset: off_t)
                -> *mut ::c_void;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "munmap$UNIX2003")]
    pub fn munmap(addr: *mut ::c_void, len: ::size_t) -> ::c_int;

    pub fn if_nametoindex(ifname: *const c_char) -> ::c_uint;

    #[cfg_attr(target_os = "macos", link_name = "lstat$INODE64")]
    #[cfg_attr(target_os = "netbsd", link_name = "__lstat50")]
    pub fn lstat(path: *const c_char, buf: *mut stat) -> ::c_int;

    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "fsync$UNIX2003")]
    pub fn fsync(fd: ::c_int) -> ::c_int;

    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "setenv$UNIX2003")]
    pub fn setenv(name: *const c_char, val: *const c_char,
                  overwrite: ::c_int) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "unsetenv$UNIX2003")]
    #[cfg_attr(target_os = "netbsd", link_name = "__unsetenv13")]
    pub fn unsetenv(name: *const c_char) -> ::c_int;

    pub fn symlink(path1: *const c_char,
                   path2: *const c_char) -> ::c_int;

    pub fn ftruncate(fd: ::c_int, length: off_t) -> ::c_int;

    #[cfg_attr(target_os = "android", link_name = "bsd_signal")]
    pub fn signal(signum: ::c_int, handler: sighandler_t) -> sighandler_t;

    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "getrlimit$UNIX2003")]
    pub fn getrlimit(resource: ::c_int, rlim: *mut rlimit) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "setrlimit$UNIX2003")]
    pub fn setrlimit(resource: ::c_int, rlim: *const rlimit) -> ::c_int;
    #[cfg_attr(target_os = "netbsd", link_name = "__getrusage50")]
    pub fn getrusage(resource: ::c_int, usage: *mut rusage) -> ::c_int;

    pub fn getdtablesize() -> ::c_int;
    #[cfg_attr(any(target_os = "macos", target_os = "ios"),
               link_name = "realpath$DARWIN_EXTSN")]
    pub fn realpath(pathname: *const ::c_char, resolved: *mut ::c_char)
                    -> *mut ::c_char;

    pub fn flock(fd: ::c_int, operation: ::c_int) -> ::c_int;

    #[cfg_attr(arget_os = "netbsd", link_name = "__gettimeofday50")]
    pub fn gettimeofday(tp: *mut ::timeval,
                        tz: *mut ::c_void) -> ::c_int;

    pub fn pthread_self() -> ::pthread_t;
    pub fn pthread_create(native: *mut ::pthread_t,
                          attr: *const ::pthread_attr_t,
                          f: extern fn(*mut ::c_void) -> *mut ::c_void,
                          value: *mut ::c_void) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "pthread_join$UNIX2003")]
    pub fn pthread_join(native: ::pthread_t,
                        value: *mut *mut ::c_void) -> ::c_int;
    pub fn pthread_attr_init(attr: *mut ::pthread_attr_t) -> ::c_int;
    pub fn pthread_attr_destroy(attr: *mut ::pthread_attr_t) -> ::c_int;
    pub fn pthread_attr_setstacksize(attr: *mut ::pthread_attr_t,
                                     stack_size: ::size_t) -> ::c_int;
    pub fn pthread_attr_setdetachstate(attr: *mut ::pthread_attr_t,
                                       state: ::c_int) -> ::c_int;
    pub fn pthread_detach(thread: ::pthread_t) -> ::c_int;
    #[cfg_attr(target_os = "netbsd", link_name = "__libc_thr_yield")]
    pub fn sched_yield() -> ::c_int;
    pub fn pthread_key_create(key: *mut pthread_key_t,
                              dtor: ::dox::Option<unsafe extern fn(*mut ::c_void)>)
                              -> ::c_int;
    pub fn pthread_key_delete(key: pthread_key_t) -> ::c_int;
    pub fn pthread_getspecific(key: pthread_key_t) -> *mut ::c_void;
    pub fn pthread_setspecific(key: pthread_key_t, value: *const ::c_void)
                               -> ::c_int;
    pub fn pthread_mutex_init(lock: *mut pthread_mutex_t,
                              attr: *const pthread_mutexattr_t) -> ::c_int;
    pub fn pthread_mutex_destroy(lock: *mut pthread_mutex_t) -> ::c_int;
    pub fn pthread_mutex_lock(lock: *mut pthread_mutex_t) -> ::c_int;
    pub fn pthread_mutex_trylock(lock: *mut pthread_mutex_t) -> ::c_int;
    pub fn pthread_mutex_unlock(lock: *mut pthread_mutex_t) -> ::c_int;

    pub fn pthread_mutexattr_init(attr: *mut pthread_mutexattr_t) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "pthread_mutexattr_destroy$UNIX2003")]
    pub fn pthread_mutexattr_destroy(attr: *mut pthread_mutexattr_t) -> ::c_int;
    pub fn pthread_mutexattr_settype(attr: *mut pthread_mutexattr_t,
                                     _type: ::c_int) -> ::c_int;

    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "pthread_cond_wait$UNIX2003")]
    pub fn pthread_cond_wait(cond: *mut pthread_cond_t,
                             lock: *mut pthread_mutex_t) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "pthread_cond_timedwait$UNIX2003")]
    pub fn pthread_cond_timedwait(cond: *mut pthread_cond_t,
                              lock: *mut pthread_mutex_t,
                              abstime: *const ::timespec) -> ::c_int;
    pub fn pthread_cond_signal(cond: *mut pthread_cond_t) -> ::c_int;
    pub fn pthread_cond_broadcast(cond: *mut pthread_cond_t) -> ::c_int;
    pub fn pthread_cond_destroy(cond: *mut pthread_cond_t) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "pthread_rwlock_destroy$UNIX2003")]
    pub fn pthread_rwlock_destroy(lock: *mut pthread_rwlock_t) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "pthread_rwlock_rdlock$UNIX2003")]
    pub fn pthread_rwlock_rdlock(lock: *mut pthread_rwlock_t) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "pthread_rwlock_tryrdlock$UNIX2003")]
    pub fn pthread_rwlock_tryrdlock(lock: *mut pthread_rwlock_t) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "pthread_rwlock_wrlock$UNIX2003")]
    pub fn pthread_rwlock_wrlock(lock: *mut pthread_rwlock_t) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "pthread_rwlock_trywrlock$UNIX2003")]
    pub fn pthread_rwlock_trywrlock(lock: *mut pthread_rwlock_t) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "pthread_rwlock_unlock$UNIX2003")]
    pub fn pthread_rwlock_unlock(lock: *mut pthread_rwlock_t) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "pthread_sigmask$UNIX2003")]
    pub fn pthread_sigmask(how: ::c_int, set: *const sigset_t,
                           oldset: *mut sigset_t) -> ::c_int;

    // #[cfg_attr(target_os = "linux", link_name = "__xpg_strerror_r")]
    pub fn strerror_r(errnum: ::c_int, buf: *mut c_char,
                      buflen: ::size_t) -> ::c_int;

    pub fn getsockopt(sockfd: ::c_int,
                      level: ::c_int,
                      optname: ::c_int,
                      optval: *mut ::c_void,
                      optlen: *mut ::socklen_t) -> ::c_int;
    pub fn raise(signum: ::c_int) -> ::c_int;
    pub fn sigaction(signum: ::c_int,
                     act: *const sigaction,
                     oldact: *mut sigaction) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "sigaltstack$UNIX2003")]
    pub fn sigaltstack(ss: *const stack_t,
                       oss: *mut stack_t) -> ::c_int;

    #[cfg_attr(target_os = "netbsd", link_name = "__utimes50")]
    pub fn utimes(filename: *const ::c_char,
                  times: *const ::timeval) -> ::c_int;
    pub fn dlopen(filename: *const ::c_char,
                  flag: ::c_int) -> *mut ::c_void;
    pub fn dlerror() -> *mut ::c_char;
    pub fn dlsym(handle: *mut ::c_void,
                 symbol: *const ::c_char) -> *mut ::c_void;
    pub fn dlclose(handle: *mut ::c_void) -> ::c_int;
    pub fn dladdr(addr: *const ::c_void, info: *mut Dl_info) -> ::c_int;

    pub fn getaddrinfo(node: *const c_char,
                       service: *const c_char,
                       hints: *const addrinfo,
                       res: *mut *mut addrinfo) -> ::c_int;
    pub fn freeaddrinfo(res: *mut addrinfo);
    pub fn gai_strerror(errcode: ::c_int) -> *const ::c_char;

    #[cfg_attr(target_os = "netbsd", link_name = "__gmtime_r50")]
    pub fn gmtime_r(time_p: *const time_t, result: *mut tm) -> *mut tm;
    #[cfg_attr(target_os = "netbsd", link_name = "__localtime_r50")]
    pub fn localtime_r(time_p: *const time_t, result: *mut tm) -> *mut tm;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "mktime$UNIX2003")]
    #[cfg_attr(target_os = "netbsd", link_name = "__mktime50")]
    pub fn mktime(tm: *mut tm) -> time_t;

    #[cfg_attr(target_os = "netbsd", link_name = "__mknod50")]
    pub fn mknod(pathname: *const ::c_char, mode: ::mode_t,
                 dev: ::dev_t) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "writev$UNIX2003")]
    pub fn writev(fd: ::c_int, iov: *const ::iovec, iovcnt: ::c_int) -> ::ssize_t;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "readv$UNIX2003")]
    pub fn readv(fd: ::c_int, iov: *const ::iovec, iovcnt: ::c_int) -> ::ssize_t;
    pub fn uname(buf: *mut ::utsname) -> ::c_int;
    pub fn daemon(nochdir: ::c_int, noclose: ::c_int) -> ::c_int;
    pub fn gethostname(name: *mut ::c_char, len: ::size_t) -> ::c_int;
    pub fn chroot(name: *const ::c_char) -> ::c_int;
}

// TODO: get rid of this #[cfg(not(...))]
#[cfg(not(target_os = "android"))]
extern {
    pub fn getifaddrs(ifap: *mut *mut ifaddrs) -> ::c_int;
    pub fn freeifaddrs(ifa: *mut ifaddrs);
    #[cfg_attr(target_os = "macos", link_name = "glob$INODE64")]
    #[cfg_attr(target_os = "netbsd", link_name = "__glob30")]
    pub fn glob(pattern: *const c_char,
                flags: ::c_int,
                errfunc: ::dox::Option<extern "C" fn(epath: *const c_char,
                                                     errno: ::c_int) -> ::c_int>,
                pglob: *mut glob_t) -> ::c_int;
    #[cfg_attr(target_os = "netbsd", link_name = "__globfree30")]
    pub fn globfree(pglob: *mut glob_t);

    pub fn posix_madvise(addr: *mut ::c_void, len: ::size_t, advice: ::c_int)
                         -> ::c_int;

    pub fn shm_unlink(name: *const c_char) -> ::c_int;

    #[cfg_attr(all(target_os = "macos", target_arch = "x86_64"),
               link_name = "seekdir$INODE64")]
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "seekdir$INODE64$UNIX2003")]
    pub fn seekdir(dirp: *mut ::DIR, loc: c_long);

    #[cfg_attr(all(target_os = "macos", target_arch = "x86_64"),
               link_name = "telldir$INODE64")]
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "telldir$INODE64$UNIX2003")]
    pub fn telldir(dirp: *mut ::DIR) -> c_long;

    pub fn getsid(pid: pid_t) -> pid_t;
    pub fn madvise(addr: *mut ::c_void, len: ::size_t, advice: ::c_int)
                   -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "putenv$UNIX2003")]
    #[cfg_attr(target_os = "netbsd", link_name = "__putenv50")]
    pub fn putenv(string: *mut c_char) -> ::c_int;
    pub fn readlink(path: *const c_char,
                    buf: *mut c_char,
                    bufsz: ::size_t)
                    -> ::ssize_t;

    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "msync$UNIX2003")]
    #[cfg_attr(target_os = "netbsd", link_name = "__msync13")]
    pub fn msync(addr: *mut ::c_void, len: ::size_t, flags: ::c_int) -> ::c_int;
    pub fn sysconf(name: ::c_int) -> c_long;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "usleep$UNIX2003")]
    pub fn usleep(secs: ::c_uint) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "recvfrom$UNIX2003")]
    pub fn recvfrom(socket: ::c_int, buf: *mut ::c_void, len: ::size_t,
                    flags: ::c_int, addr: *mut sockaddr,
                    addrlen: *mut socklen_t) -> ::ssize_t;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "send$UNIX2003")]
    pub fn send(socket: ::c_int, buf: *const ::c_void, len: ::size_t,
                flags: ::c_int) -> ::ssize_t;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "recv$UNIX2003")]
    pub fn recv(socket: ::c_int, buf: *mut ::c_void, len: ::size_t,
                flags: ::c_int) -> ::ssize_t;
    pub fn mkfifo(path: *const c_char, mode: mode_t) -> ::c_int;

    #[cfg_attr(target_os = "netbsd", link_name = "__getpwuid_r50")]
    pub fn getpwuid_r(uid: ::uid_t,
                      pwd: *mut passwd,
                      buf: *mut ::c_char,
                      buflen: ::size_t,
                      result: *mut *mut passwd) -> ::c_int;
    pub fn posix_memalign(memptr: *mut *mut ::c_void,
                          align: ::size_t,
                          size: ::size_t) -> ::c_int;
    #[cfg_attr(target_os = "netbsd", link_name = "__sigemptyset14")]
    pub fn sigemptyset(set: *mut sigset_t) -> ::c_int;
    #[cfg_attr(target_os = "netbsd", link_name = "__sigaddset14")]
    pub fn sigaddset(set: *mut sigset_t, signum: ::c_int) -> ::c_int;
    #[cfg_attr(target_os = "netbsd", link_name = "__sigfillset14")]
    pub fn sigfillset(set: *mut sigset_t) -> ::c_int;
    #[cfg_attr(target_os = "netbsd", link_name = "__sigdelset14")]
    pub fn sigdelset(set: *mut sigset_t, signum: ::c_int) -> ::c_int;
    #[cfg_attr(target_os = "netbsd", link_name = "__sigismember14")]
    pub fn sigismember(set: *const sigset_t, signum: ::c_int) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86_64"),
               link_name = "select$1050")]
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "select$UNIX2003")]
    #[cfg_attr(target_os = "netbsd", link_name = "__select50")]
    pub fn select(nfds: ::c_int,
                  readfs: *mut fd_set,
                  writefds: *mut fd_set,
                  errorfds: *mut fd_set,
                  timeout: *mut timeval) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86_64"),
               link_name = "pselect$1050")]
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "pselect$UNIX2003")]
    #[cfg_attr(target_os = "netbsd", link_name = "__pselect50")]
    pub fn pselect(nfds: ::c_int,
                   readfs: *mut fd_set,
                   writefds: *mut fd_set,
                   errorfds: *mut fd_set,
                   timeout: *const timespec,
                   sigmask: *const sigset_t) -> ::c_int;
    pub fn fseeko(stream: *mut ::FILE,
                  offset: ::off_t,
                  whence: ::c_int) -> ::c_int;
    pub fn ftello(stream: *mut ::FILE) -> ::off_t;
    #[cfg_attr(target_os = "netbsd", link_name = "__timegm50")]
    pub fn timegm(tm: *mut ::tm) -> time_t;
    pub fn statvfs(path: *const c_char, buf: *mut statvfs) -> ::c_int;
    pub fn fstatvfs(fd: ::c_int, buf: *mut statvfs) -> ::c_int;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "sendmsg$UNIX2003")]
    pub fn sendmsg(fd: ::c_int, msg: *const msghdr, flags: ::c_int) -> ::ssize_t;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "recvmsg$UNIX2003")]
    pub fn recvmsg(fd: ::c_int, msg: *mut msghdr, flags: ::c_int) -> ::ssize_t;
    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
               link_name = "tcdrain$UNIX2003")]
    pub fn tcdrain(fd: ::c_int) -> ::c_int;
    pub fn cfgetispeed(termios: *const ::termios) -> ::speed_t;
    pub fn cfgetospeed(termios: *const ::termios) -> ::speed_t;
    pub fn cfsetispeed(termios: *mut ::termios, speed: ::speed_t) -> ::c_int;
    pub fn cfsetospeed(termios: *mut ::termios, speed: ::speed_t) -> ::c_int;
    pub fn tcgetattr(fd: ::c_int, termios: *mut ::termios) -> ::c_int;
    pub fn tcsetattr(fd: ::c_int,
                     optional_actions: ::c_int,
                     termios: *const ::termios) -> ::c_int;
    pub fn tcflow(fd: ::c_int, action: ::c_int) -> ::c_int;
    pub fn tcflush(fd: ::c_int, action: ::c_int) -> ::c_int;
    pub fn tcsendbreak(fd: ::c_int, duration: ::c_int) -> ::c_int;
}

cfg_if! {
    if #[cfg(any(target_os = "linux", target_os = "android"))] {
        mod notbsd;
        pub use self::notbsd::*;
    } else if #[cfg(any(target_os = "macos",
                        target_os = "ios",
                        target_os = "freebsd",
                        target_os = "dragonfly",
                        target_os = "openbsd",
                        target_os = "netbsd",
                        target_os = "bitrig"))] {
        mod bsd;
        pub use self::bsd::*;
    } else {
        // ...
    }
}