POSIX::redef setv?buf() to IO::Handle:: (by gbarr).

[perl5.git] / ext / POSIX / POSIX.pm

package POSIX;

use vars qw($VERSION @ISA %EXPORT_TAGS @EXPORT_OK $AUTOLOAD); 

use Carp;
use AutoLoader;
require Config;
use Symbol;

require Exporter;
require DynaLoader;
@ISA = qw(Exporter DynaLoader);

$VERSION = "1.02" ;

%EXPORT_TAGS = (

    assert_h => [qw(assert NDEBUG)],

    ctype_h =>  [qw(isalnum isalpha iscntrl isdigit isgraph islower
                isprint ispunct isspace isupper isxdigit tolower toupper)],

    dirent_h => [qw()],

    errno_h =>  [qw(E2BIG EACCES EADDRINUSE EADDRNOTAVAIL EAFNOSUPPORT
                EAGAIN EALREADY EBADF EBUSY ECHILD ECONNABORTED
                ECONNREFUSED ECONNRESET EDEADLK EDESTADDRREQ EDOM EDQUOT
                EEXIST EFAULT EFBIG EHOSTDOWN EHOSTUNREACH EINPROGRESS
                EINTR EINVAL EIO EISCONN EISDIR ELOOP EMFILE EMLINK
                EMSGSIZE ENAMETOOLONG ENETDOWN ENETRESET ENETUNREACH
                ENFILE ENOBUFS ENODEV ENOENT ENOEXEC ENOLCK ENOMEM
                ENOPROTOOPT ENOSPC ENOSYS ENOTBLK ENOTCONN ENOTDIR
                ENOTEMPTY ENOTSOCK ENOTTY ENXIO EOPNOTSUPP EPERM
                EPFNOSUPPORT EPIPE EPROCLIM EPROTONOSUPPORT EPROTOTYPE
                ERANGE EREMOTE ERESTART EROFS ESHUTDOWN ESOCKTNOSUPPORT
                ESPIPE ESRCH ESTALE ETIMEDOUT ETOOMANYREFS ETXTBSY
                EUSERS EWOULDBLOCK EXDEV errno)],

    fcntl_h =>  [qw(FD_CLOEXEC F_DUPFD F_GETFD F_GETFL F_GETLK F_RDLCK
                F_SETFD F_SETFL F_SETLK F_SETLKW F_UNLCK F_WRLCK
                O_ACCMODE O_APPEND O_CREAT O_EXCL O_NOCTTY O_NONBLOCK
                O_RDONLY O_RDWR O_TRUNC O_WRONLY
                creat
                SEEK_CUR SEEK_END SEEK_SET
                S_IRGRP S_IROTH S_IRUSR S_IRWXG S_IRWXO S_IRWXU
                S_ISBLK S_ISCHR S_ISDIR S_ISFIFO S_ISGID S_ISREG S_ISUID
                S_IWGRP S_IWOTH S_IWUSR)],

    float_h =>  [qw(DBL_DIG DBL_EPSILON DBL_MANT_DIG
                DBL_MAX DBL_MAX_10_EXP DBL_MAX_EXP
                DBL_MIN DBL_MIN_10_EXP DBL_MIN_EXP
                FLT_DIG FLT_EPSILON FLT_MANT_DIG
                FLT_MAX FLT_MAX_10_EXP FLT_MAX_EXP
                FLT_MIN FLT_MIN_10_EXP FLT_MIN_EXP
                FLT_RADIX FLT_ROUNDS
                LDBL_DIG LDBL_EPSILON LDBL_MANT_DIG
                LDBL_MAX LDBL_MAX_10_EXP LDBL_MAX_EXP
                LDBL_MIN LDBL_MIN_10_EXP LDBL_MIN_EXP)],

    grp_h =>    [qw()],

    limits_h => [qw( ARG_MAX CHAR_BIT CHAR_MAX CHAR_MIN CHILD_MAX
                INT_MAX INT_MIN LINK_MAX LONG_MAX LONG_MIN MAX_CANON
                MAX_INPUT MB_LEN_MAX NAME_MAX NGROUPS_MAX OPEN_MAX
                PATH_MAX PIPE_BUF SCHAR_MAX SCHAR_MIN SHRT_MAX SHRT_MIN
                SSIZE_MAX STREAM_MAX TZNAME_MAX UCHAR_MAX UINT_MAX
                ULONG_MAX USHRT_MAX _POSIX_ARG_MAX _POSIX_CHILD_MAX
                _POSIX_LINK_MAX _POSIX_MAX_CANON _POSIX_MAX_INPUT
                _POSIX_NAME_MAX _POSIX_NGROUPS_MAX _POSIX_OPEN_MAX
                _POSIX_PATH_MAX _POSIX_PIPE_BUF _POSIX_SSIZE_MAX
                _POSIX_STREAM_MAX _POSIX_TZNAME_MAX)],

    locale_h => [qw(LC_ALL LC_COLLATE LC_CTYPE LC_MONETARY LC_NUMERIC
                LC_TIME NULL localeconv setlocale)],

    math_h =>   [qw(HUGE_VAL acos asin atan ceil cosh fabs floor fmod
                frexp ldexp log10 modf pow sinh tan tanh)],

    pwd_h =>    [qw()],

    setjmp_h => [qw(longjmp setjmp siglongjmp sigsetjmp)],

    signal_h => [qw(SA_NOCLDSTOP SA_NOCLDWAIT SA_NODEFER SA_ONSTACK
                SA_RESETHAND SA_RESTART SA_SIGINFO SIGABRT SIGALRM
                SIGCHLD SIGCONT SIGFPE SIGHUP SIGILL SIGINT SIGKILL
                SIGPIPE SIGQUIT SIGSEGV SIGSTOP SIGTERM SIGTSTP SIGTTIN
                SIGTTOU SIGUSR1 SIGUSR2 SIG_BLOCK SIG_DFL SIG_ERR
                SIG_IGN SIG_SETMASK SIG_UNBLOCK raise sigaction signal
                sigpending sigprocmask sigsuspend)],

    stdarg_h => [qw()],

    stddef_h => [qw(NULL offsetof)],

    stdio_h =>  [qw(BUFSIZ EOF FILENAME_MAX L_ctermid L_cuserid
                L_tmpname NULL SEEK_CUR SEEK_END SEEK_SET
                STREAM_MAX TMP_MAX stderr stdin stdout
                clearerr fclose fdopen feof ferror fflush fgetc fgetpos
                fgets fopen fprintf fputc fputs fread freopen
                fscanf fseek fsetpos ftell fwrite getchar gets
                perror putc putchar puts remove rewind
                scanf setbuf setvbuf sscanf tmpfile tmpnam
                ungetc vfprintf vprintf vsprintf)],

    stdlib_h => [qw(EXIT_FAILURE EXIT_SUCCESS MB_CUR_MAX NULL RAND_MAX
                abort atexit atof atoi atol bsearch calloc div
                free getenv labs ldiv malloc mblen mbstowcs mbtowc
                qsort realloc strtod strtol strtoul wcstombs wctomb)],

    string_h => [qw(NULL memchr memcmp memcpy memmove memset strcat
                strchr strcmp strcoll strcpy strcspn strerror strlen
                strncat strncmp strncpy strpbrk strrchr strspn strstr
                strtok strxfrm)],

    sys_stat_h => [qw(S_IRGRP S_IROTH S_IRUSR S_IRWXG S_IRWXO S_IRWXU
                S_ISBLK S_ISCHR S_ISDIR S_ISFIFO S_ISGID S_ISREG
                S_ISUID S_IWGRP S_IWOTH S_IWUSR S_IXGRP S_IXOTH S_IXUSR
                fstat mkfifo)],

    sys_times_h => [qw()],

    sys_types_h => [qw()],

    sys_utsname_h => [qw(uname)],

    sys_wait_h => [qw(WEXITSTATUS WIFEXITED WIFSIGNALED WIFSTOPPED
                WNOHANG WSTOPSIG WTERMSIG WUNTRACED)],

    termios_h => [qw( B0 B110 B1200 B134 B150 B1800 B19200 B200 B2400
                B300 B38400 B4800 B50 B600 B75 B9600 BRKINT CLOCAL
                CREAD CS5 CS6 CS7 CS8 CSIZE CSTOPB ECHO ECHOE ECHOK
                ECHONL HUPCL ICANON ICRNL IEXTEN IGNBRK IGNCR IGNPAR
                INLCR INPCK ISIG ISTRIP IXOFF IXON NCCS NOFLSH OPOST
                PARENB PARMRK PARODD TCIFLUSH TCIOFF TCIOFLUSH TCION
                TCOFLUSH TCOOFF TCOON TCSADRAIN TCSAFLUSH TCSANOW
                TOSTOP VEOF VEOL VERASE VINTR VKILL VMIN VQUIT VSTART
                VSTOP VSUSP VTIME
                cfgetispeed cfgetospeed cfsetispeed cfsetospeed tcdrain
                tcflow tcflush tcgetattr tcsendbreak tcsetattr )],

    time_h =>   [qw(CLK_TCK CLOCKS_PER_SEC NULL asctime clock ctime
                difftime mktime strftime tzset tzname)],

    unistd_h => [qw(F_OK NULL R_OK SEEK_CUR SEEK_END SEEK_SET
                STRERR_FILENO STDIN_FILENO STDOUT_FILENO W_OK X_OK
                _PC_CHOWN_RESTRICTED _PC_LINK_MAX _PC_MAX_CANON
                _PC_MAX_INPUT _PC_NAME_MAX _PC_NO_TRUNC _PC_PATH_MAX
                _PC_PIPE_BUF _PC_VDISABLE _POSIX_CHOWN_RESTRICTED
                _POSIX_JOB_CONTROL _POSIX_NO_TRUNC _POSIX_SAVED_IDS
                _POSIX_VDISABLE _POSIX_VERSION _SC_ARG_MAX
                _SC_CHILD_MAX _SC_CLK_TCK _SC_JOB_CONTROL
                _SC_NGROUPS_MAX _SC_OPEN_MAX _SC_SAVED_IDS
                _SC_STREAM_MAX _SC_TZNAME_MAX _SC_VERSION
                _exit access ctermid cuserid
                dup2 dup execl execle execlp execv execve execvp
                fpathconf getcwd getegid geteuid getgid getgroups
                getpid getuid isatty lseek pathconf pause setgid setpgid
                setsid setuid sysconf tcgetpgrp tcsetpgrp ttyname)],

    utime_h =>  [qw()],

);

Exporter::export_tags();

@EXPORT_OK = qw(
    closedir opendir readdir rewinddir
    fcntl open
    getgrgid getgrnam
    atan2 cos exp log sin sqrt
    getpwnam getpwuid
    kill
    fileno getc printf rename sprintf
    abs exit rand srand system
    chmod mkdir stat umask
    times
    wait waitpid
    gmtime localtime time 
    alarm chdir chown close fork getlogin getppid getpgrp link
        pipe read rmdir sleep unlink write
    utime
    nice
);

# Grandfather old foo_h form to new :foo_h form
sub import {
    my $this = shift;
    my @list = map { m/^\w+_h$/ ? ":$_" : $_ } @_;
    local $Exporter::ExportLevel = 1;
    Exporter::import($this,@list);
}


bootstrap POSIX $VERSION;

my $EINVAL = constant("EINVAL", 0);
my $EAGAIN = constant("EAGAIN", 0);

sub AUTOLOAD {
    if ($AUTOLOAD =~ /::(_?[a-z])/) {
        $AutoLoader::AUTOLOAD = $AUTOLOAD;
        goto &AutoLoader::AUTOLOAD
    }
    local $! = 0;
    my $constname = $AUTOLOAD;
    $constname =~ s/.*:://;
    my $val = constant($constname, @_ ? $_[0] : 0);
    if ($! == 0) {
        *$AUTOLOAD = sub { $val };
    }
    elsif ($! == $EAGAIN) {     # Not really a constant, so always call.
        *$AUTOLOAD = sub { constant($constname, $_[0]) };
    }
    elsif ($! == $EINVAL) {
        croak "$constname is not a valid POSIX macro";
    }
    else {
        croak "Your vendor has not defined POSIX macro $constname, used";
    }

    goto &$AUTOLOAD;
}

sub usage { 
    my ($mess) = @_;
    croak "Usage: POSIX::$mess";
}

sub redef { 
    my ($mess) = @_;
    croak "Use method $mess instead";
}

sub unimpl { 
    my ($mess) = @_;
    $mess =~ s/xxx//;
    croak "Unimplemented: POSIX::$mess";
}

############################
package POSIX::SigAction;

sub new {
    bless {HANDLER => $_[1], MASK => $_[2], FLAGS => $_[3] || 0}, $_[0];
}

############################
package POSIX; # return to package POSIX so AutoSplit is happy
1;
__END__

sub assert {
    usage "assert(expr)" if @_ != 1;
    if (!$_[0]) {
        croak "Assertion failed";
    }
}

sub tolower {
    usage "tolower(string)" if @_ != 1;
    lc($_[0]);
}

sub toupper {
    usage "toupper(string)" if @_ != 1;
    uc($_[0]);
}

sub closedir {
    usage "closedir(dirhandle)" if @_ != 1;
    CORE::closedir($_[0]);
}

sub opendir {
    usage "opendir(directory)" if @_ != 1;
    my $dirhandle = gensym;
    CORE::opendir($dirhandle, $_[0])
        ? $dirhandle
        : undef;
}

sub readdir {
    usage "readdir(dirhandle)" if @_ != 1;
    CORE::readdir($_[0]);
}

sub rewinddir {
    usage "rewinddir(dirhandle)" if @_ != 1;
    CORE::rewinddir($_[0]);
}

sub errno {
    usage "errno()" if @_ != 0;
    $! + 0;
}

sub creat {
    usage "creat(filename, mode)" if @_ != 2;
    &open($_[0], &O_WRONLY | &O_CREAT | &O_TRUNC, $_[1]);
}

sub fcntl {
    usage "fcntl(filehandle, cmd, arg)" if @_ != 3;
    CORE::fcntl($_[0], $_[1], $_[2]);
}

sub getgrgid {
    usage "getgrgid(gid)" if @_ != 1;
    CORE::getgrgid($_[0]);
}

sub getgrnam {
    usage "getgrnam(name)" if @_ != 1;
    CORE::getgrnam($_[0]);
}

sub atan2 {
    usage "atan2(x,y)" if @_ != 2;
    CORE::atan2($_[0], $_[1]);
}

sub cos {
    usage "cos(x)" if @_ != 1;
    CORE::cos($_[0]);
}

sub exp {
    usage "exp(x)" if @_ != 1;
    CORE::exp($_[0]);
}

sub fabs {
    usage "fabs(x)" if @_ != 1;
    CORE::abs($_[0]);
}

sub log {
    usage "log(x)" if @_ != 1;
    CORE::log($_[0]);
}

sub pow {
    usage "pow(x,exponent)" if @_ != 2;
    $_[0] ** $_[1];
}

sub sin {
    usage "sin(x)" if @_ != 1;
    CORE::sin($_[0]);
}

sub sqrt {
    usage "sqrt(x)" if @_ != 1;
    CORE::sqrt($_[0]);
}

sub getpwnam {
    usage "getpwnam(name)" if @_ != 1;
    CORE::getpwnam($_[0]);
}

sub getpwuid {
    usage "getpwuid(uid)" if @_ != 1;
    CORE::getpwuid($_[0]);
}

sub longjmp {
    unimpl "longjmp() is C-specific: use die instead";
}

sub setjmp {
    unimpl "setjmp() is C-specific: use eval {} instead";
}

sub siglongjmp {
    unimpl "siglongjmp() is C-specific: use die instead";
}

sub sigsetjmp {
    unimpl "sigsetjmp() is C-specific: use eval {} instead";
}

sub kill {
    usage "kill(pid, sig)" if @_ != 2;
    CORE::kill $_[1], $_[0];
}

sub raise {
    usage "raise(sig)" if @_ != 1;
    CORE::kill $_[0], $$;       # Is this good enough?
}

sub offsetof {
    unimpl "offsetof() is C-specific, stopped";
}

sub clearerr {
    redef "IO::Handle::clearerr()";
}

sub fclose {
    redef "IO::Handle::close()";
}

sub fdopen {
    redef "IO::Handle::new_from_fd()";
}

sub feof {
    redef "IO::Handle::eof()";
}

sub fgetc {
    redef "IO::Handle::getc()";
}

sub fgets {
    redef "IO::Handle::gets()";
}

sub fileno {
    redef "IO::Handle::fileno()";
}

sub fopen {
    redef "IO::File::open()";
}

sub fprintf {
    unimpl "fprintf() is C-specific--use printf instead";
}

sub fputc {
    unimpl "fputc() is C-specific--use print instead";
}

sub fputs {
    unimpl "fputs() is C-specific--use print instead";
}

sub fread {
    unimpl "fread() is C-specific--use read instead";
}

sub freopen {
    unimpl "freopen() is C-specific--use open instead";
}

sub fscanf {
    unimpl "fscanf() is C-specific--use <> and regular expressions instead";
}

sub fseek {
    redef "IO::Seekable::seek()";
}

sub ferror {
    redef "IO::Handle::error()";
}

sub fflush {
    redef "IO::Handle::flush()";
}

sub fgetpos {
    redef "IO::Seekable::getpos()";
}

sub fsetpos {
    redef "IO::Seekable::setpos()";
}

sub ftell {
    redef "IO::Seekable::tell()";
}

sub fwrite {
    unimpl "fwrite() is C-specific--use print instead";
}

sub getc {
    usage "getc(handle)" if @_ != 1;
    CORE::getc($_[0]);
}

sub getchar {
    usage "getchar()" if @_ != 0;
    CORE::getc(STDIN);
}

sub gets {
    usage "gets()" if @_ != 0;
    scalar <STDIN>;
}

sub perror {
    print STDERR "@_: " if @_;
    print STDERR $!,"\n";
}

sub printf {
    usage "printf(pattern, args...)" if @_ < 1;
    CORE::printf STDOUT @_;
}

sub putc {
    unimpl "putc() is C-specific--use print instead";
}

sub putchar {
    unimpl "putchar() is C-specific--use print instead";
}

sub puts {
    unimpl "puts() is C-specific--use print instead";
}

sub remove {
    usage "remove(filename)" if @_ != 1;
    CORE::unlink($_[0]);
}

sub rename {
    usage "rename(oldfilename, newfilename)" if @_ != 2;
    CORE::rename($_[0], $_[1]);
}

sub rewind {
    usage "rewind(filehandle)" if @_ != 1;
    CORE::seek($_[0],0,0);
}

sub scanf {
    unimpl "scanf() is C-specific--use <> and regular expressions instead";
}

sub sprintf {
    usage "sprintf(pattern,args)" if @_ == 0;
    CORE::sprintf(shift,@_);
}

sub sscanf {
    unimpl "sscanf() is C-specific--use regular expressions instead";
}

sub tmpfile {
    redef "IO::File::new_tmpfile()";
}

sub ungetc {
    redef "IO::Handle::ungetc()";
}

sub vfprintf {
    unimpl "vfprintf() is C-specific";
}

sub vprintf {
    unimpl "vprintf() is C-specific";
}

sub vsprintf {
    unimpl "vsprintf() is C-specific";
}

sub abs {
    usage "abs(x)" if @_ != 1;
    CORE::abs($_[0]);
}

sub atexit {
    unimpl "atexit() is C-specific: use END {} instead";
}

sub atof {
    unimpl "atof() is C-specific, stopped";
}

sub atoi {
    unimpl "atoi() is C-specific, stopped";
}

sub atol {
    unimpl "atol() is C-specific, stopped";
}

sub bsearch {
    unimpl "bsearch() not supplied";
}

sub calloc {
    unimpl "calloc() is C-specific, stopped";
}

sub div {
    unimpl "div() is C-specific, stopped";
}

sub exit {
    usage "exit(status)" if @_ != 1;
    CORE::exit($_[0]);
}

sub free {
    unimpl "free() is C-specific, stopped";
}

sub getenv {
    usage "getenv(name)" if @_ != 1;
    $ENV{$_[0]};
}

sub labs {
    unimpl "labs() is C-specific, use abs instead";
}

sub ldiv {
    unimpl "ldiv() is C-specific, use / and int instead";
}

sub malloc {
    unimpl "malloc() is C-specific, stopped";
}

sub qsort {
    unimpl "qsort() is C-specific, use sort instead";
}

sub rand {
    unimpl "rand() is non-portable, use Perl's rand instead";
}

sub realloc {
    unimpl "realloc() is C-specific, stopped";
}

sub srand {
    unimpl "srand()";
}

sub system {
    usage "system(command)" if @_ != 1;
    CORE::system($_[0]);
}

sub memchr {
    unimpl "memchr() is C-specific, use index() instead";
}

sub memcmp {
    unimpl "memcmp() is C-specific, use eq instead";
}

sub memcpy {
    unimpl "memcpy() is C-specific, use = instead";
}

sub memmove {
    unimpl "memmove() is C-specific, use = instead";
}

sub memset {
    unimpl "memset() is C-specific, use x instead";
}

sub strcat {
    unimpl "strcat() is C-specific, use .= instead";
}

sub strchr {
    unimpl "strchr() is C-specific, use index() instead";
}

sub strcmp {
    unimpl "strcmp() is C-specific, use eq instead";
}

sub strcpy {
    unimpl "strcpy() is C-specific, use = instead";
}

sub strcspn {
    unimpl "strcspn() is C-specific, use regular expressions instead";
}

sub strerror {
    usage "strerror(errno)" if @_ != 1;
    local $! = $_[0];
    $! . "";
}

sub strlen {
    unimpl "strlen() is C-specific, use length instead";
}

sub strncat {
    unimpl "strncat() is C-specific, use .= instead";
}

sub strncmp {
    unimpl "strncmp() is C-specific, use eq instead";
}

sub strncpy {
    unimpl "strncpy() is C-specific, use = instead";
}

sub strpbrk {
    unimpl "strpbrk() is C-specific, stopped";
}

sub strrchr {
    unimpl "strrchr() is C-specific, use rindex() instead";
}

sub strspn {
    unimpl "strspn() is C-specific, stopped";
}

sub strstr {
    usage "strstr(big, little)" if @_ != 2;
    CORE::index($_[0], $_[1]);
}

sub strtok {
    unimpl "strtok() is C-specific, stopped";
}

sub chmod {
    usage "chmod(mode, filename)" if @_ != 2;
    CORE::chmod($_[0], $_[1]);
}

sub fstat {
    usage "fstat(fd)" if @_ != 1;
    local *TMP;
    open(TMP, "<&$_[0]");               # Gross.
    my @l = CORE::stat(TMP);
    close(TMP);
    @l;
}

sub mkdir {
    usage "mkdir(directoryname, mode)" if @_ != 2;
    CORE::mkdir($_[0], $_[1]);
}

sub stat {
    usage "stat(filename)" if @_ != 1;
    CORE::stat($_[0]);
}

sub umask {
    usage "umask(mask)" if @_ != 1;
    CORE::umask($_[0]);
}

sub wait {
    usage "wait()" if @_ != 0;
    CORE::wait();
}

sub waitpid {
    usage "waitpid(pid, options)" if @_ != 2;
    CORE::waitpid($_[0], $_[1]);
}

sub gmtime {
    usage "gmtime(time)" if @_ != 1;
    CORE::gmtime($_[0]);
}

sub localtime {
    usage "localtime(time)" if @_ != 1;
    CORE::localtime($_[0]);
}

sub time {
    usage "time()" if @_ != 0;
    CORE::time;
}

sub alarm {
    usage "alarm(seconds)" if @_ != 1;
    CORE::alarm($_[0]);
}

sub chdir {
    usage "chdir(directory)" if @_ != 1;
    CORE::chdir($_[0]);
}

sub chown {
    usage "chown(filename, uid, gid)" if @_ != 3;
    CORE::chown($_[0], $_[1], $_[2]);
}

sub execl {
    unimpl "execl() is C-specific, stopped";
}

sub execle {
    unimpl "execle() is C-specific, stopped";
}

sub execlp {
    unimpl "execlp() is C-specific, stopped";
}

sub execv {
    unimpl "execv() is C-specific, stopped";
}

sub execve {
    unimpl "execve() is C-specific, stopped";
}

sub execvp {
    unimpl "execvp() is C-specific, stopped";
}

sub fork {
    usage "fork()" if @_ != 0;
    CORE::fork;
}

sub getcwd
{
    usage "getcwd()" if @_ != 0;
    if ($^O eq 'MSWin32') {
        # this perhaps applies to everyone else also?
        require Cwd;
        $cwd = &Cwd::cwd;
    }
    else {
        chop($cwd = `pwd`);
    }
    $cwd;
}

sub getegid {
    usage "getegid()" if @_ != 0;
    $) + 0;
}

sub geteuid {
    usage "geteuid()" if @_ != 0;
    $> + 0;
}

sub getgid {
    usage "getgid()" if @_ != 0;
    $( + 0;
}

sub getgroups {
    usage "getgroups()" if @_ != 0;
    my %seen;
    grep(!$seen{$_}++, split(' ', $) ));
}

sub getlogin {
    usage "getlogin()" if @_ != 0;
    CORE::getlogin();
}

sub getpgrp {
    usage "getpgrp()" if @_ != 0;
    CORE::getpgrp;
}

sub getpid {
    usage "getpid()" if @_ != 0;
    $$;
}

sub getppid {
    usage "getppid()" if @_ != 0;
    CORE::getppid;
}

sub getuid {
    usage "getuid()" if @_ != 0;
    $<;
}

sub isatty {
    usage "isatty(filehandle)" if @_ != 1;
    -t $_[0];
}

sub link {
    usage "link(oldfilename, newfilename)" if @_ != 2;
    CORE::link($_[0], $_[1]);
}

sub rmdir {
    usage "rmdir(directoryname)" if @_ != 1;
    CORE::rmdir($_[0]);
}

sub setbuf {
    redef "IO::Handle::setbuf()";
}

sub setgid {
    usage "setgid(gid)" if @_ != 1;
    $( = $_[0];
}

sub setuid {
    usage "setuid(uid)" if @_ != 1;
    $< = $_[0];
}

sub setvbuf {
    redef "IO::Handle::setvbuf()";
}

sub sleep {
    usage "sleep(seconds)" if @_ != 1;
    CORE::sleep($_[0]);
}

sub unlink {
    usage "unlink(filename)" if @_ != 1;
    CORE::unlink($_[0]);
}

sub utime {
    usage "utime(filename, atime, mtime)" if @_ != 3;
    CORE::utime($_[1], $_[2], $_[0]);
}