text: /**********************************************************************
  
    error.c -
  
    $Author: nagachika $
    created at: Mon Aug  9 16:11:34 JST 1993
  
    Copyright (C) 1993-2007 Yukihiro Matsumoto
  
  **********************************************************************/
  
  #include "ruby/ruby.h"
  #include "ruby/st.h"
  #include "ruby/encoding.h"
  #include "internal.h"
  #include "vm_core.h"
  
  #include <stdio.h>
  #include <stdarg.h>
  #ifdef HAVE_STDLIB_H
  #include <stdlib.h>
  #endif
  #include <errno.h>
  #ifdef HAVE_UNISTD_H
  #include <unistd.h>
  #endif
  
  #ifndef EXIT_SUCCESS
  #define EXIT_SUCCESS 0
  #endif
  
  #ifndef WIFEXITED
  #define WIFEXITED(status) 1
  #endif
  
  #ifndef WEXITSTATUS
  #define WEXITSTATUS(status) (status)
  #endif
  
  VALUE rb_eEAGAIN;
  VALUE rb_eEWOULDBLOCK;
  VALUE rb_eEINPROGRESS;
  
  extern const char ruby_description[];
  
  static const char REPORTBUG_MSG[] =
  	"[NOTE]\n" \
  	"You may have encountered a bug in the Ruby interpreter" \
  	" or extension libraries.\n" \
  	"Bug reports are welcome.\n" \
  	""
  #if defined __APPLE__
  	"Don't forget to include the above Crash Report log file.\n"
  #endif
  	"For details: http://www.ruby-lang.org/bugreport.html\n\n" \
      ;
  
  static const char *
  rb_strerrno(int err)
  {
  #define defined_error(name, num) if (err == (num)) return (name);
  #define undefined_error(name)
  #include "known_errors.inc"
  #undef defined_error
  #undef undefined_error
      return NULL;
  }
  
  static int
  err_position_0(char *buf, long len, const char *file, int line)
  {
      if (!file) {
  	return 0;
      }
      else if (line == 0) {
  	return snprintf(buf, len, "%s: ", file);
      }
      else {
  	return snprintf(buf, len, "%s:%d: ", file, line);
      }
  }
  
  static VALUE
  compile_snprintf(rb_encoding *enc, const char *pre, const char *file, int line, const char *fmt, va_list args)
  {
      VALUE str = rb_enc_str_new(0, 0, enc);
  
      if (file) {
  	rb_str_cat2(str, file);
  	if (line) rb_str_catf(str, ":%d", line);
  	rb_str_cat2(str, ": ");
      }
      if (pre) rb_str_cat2(str, pre);
      rb_str_vcatf(str, fmt, args);
      return str;
  }
  
  static void
  compile_err_append(VALUE mesg)
  {
      rb_thread_t *th = GET_THREAD();
      VALUE err = th->errinfo;
      rb_block_t *prev_base_block = th->base_block;
      th->base_block = 0;
      /* base_block should be zero while normal Ruby execution */
      /* after this line, any Ruby code *can* run */
  
      if (th->mild_compile_error) {
  	if (RTEST(err)) {
  	    VALUE str = rb_obj_as_string(err);
  
  	    rb_str_cat2(str, "\n");
  	    rb_str_append(str, mesg);
  	    mesg = str;
  	}
  	err = rb_exc_new3(rb_eSyntaxError, mesg);
  	th->errinfo = err;
      }
      else {
  	if (!RTEST(err)) {
  	    err = rb_exc_new2(rb_eSyntaxError, "compile error");
  	    th->errinfo = err;
  	}
  	rb_str_cat2(mesg, "\n");
  	rb_write_error_str(mesg);
      }
  
      /* returned to the parser world */
      th->base_block = prev_base_block;
  }
  
  void
  rb_compile_error_with_enc(const char *file, int line, void *enc, const char *fmt, ...)
  {
      va_list args;
      VALUE str;
  
      va_start(args, fmt);
      str = compile_snprintf(enc, NULL, file, line, fmt, args);
      va_end(args);
      compile_err_append(str);
  }
  
  void
  rb_compile_error(const char *file, int line, const char *fmt, ...)
  {
      va_list args;
      VALUE str;
  
      va_start(args, fmt);
      str = compile_snprintf(NULL, NULL, file, line, fmt, args);
      va_end(args);
      compile_err_append(str);
  }
  
  void
  rb_compile_error_append(const char *fmt, ...)
  {
      va_list args;
      VALUE str;
  
      va_start(args, fmt);
      str = rb_vsprintf(fmt, args);
      va_end(args);
      compile_err_append(str);
  }
  
  static void
  compile_warn_print(const char *file, int line, const char *fmt, va_list args)
  {
      VALUE str;
  
      str = compile_snprintf(NULL, "warning: ", file, line, fmt, args);
      rb_str_cat2(str, "\n");
      rb_write_error_str(str);
  }
  
  void
  rb_compile_warn(const char *file, int line, const char *fmt, ...)
  {
      va_list args;
  
      if (NIL_P(ruby_verbose)) return;
  
      va_start(args, fmt);
      compile_warn_print(file, line, fmt, args);
      va_end(args);
  }
  
  /* rb_compile_warning() reports only in verbose mode */
  void
  rb_compile_warning(const char *file, int line, const char *fmt, ...)
  {
      va_list args;
  
      if (!RTEST(ruby_verbose)) return;
  
      va_start(args, fmt);
      compile_warn_print(file, line, fmt, args);
      va_end(args);
  }
  
  static void
  warn_print(const char *fmt, va_list args)
  {
      VALUE str = rb_str_new(0, 0);
      VALUE file = rb_sourcefilename();
  
      if (!NIL_P(file)) {
  	int line = rb_sourceline();
  	str = rb_str_append(str, file);
  	if (line) rb_str_catf(str, ":%d", line);
  	rb_str_cat2(str, ": ");
      }
  
      rb_str_cat2(str, "warning: ");
      rb_str_vcatf(str, fmt, args);
      rb_str_cat2(str, "\n");
      rb_write_error_str(str);
  }
  
  void
  rb_warn(const char *fmt, ...)
  {
      va_list args;
  
      if (NIL_P(ruby_verbose)) return;
  
      va_start(args, fmt);
      warn_print(fmt, args);
      va_end(args);
  }
  
  /* rb_warning() reports only in verbose mode */
  void
  rb_warning(const char *fmt, ...)
  {
      va_list args;
  
      if (!RTEST(ruby_verbose)) return;
  
      va_start(args, fmt);
      warn_print(fmt, args);
      va_end(args);
  }
  
  /*
   * call-seq:
   *    warn(msg, ...)   -> nil
   *
   * Displays each of the given messages followed by a record separator on
   * STDERR unless warnings have been disabled (for example with the
   * <code>-W0</code> flag).
   *
   *    warn("warning 1", "warning 2")
   *
   *  <em>produces:</em>
   *
   *    warning 1
   *    warning 2
   */
  
  static VALUE
  rb_warn_m(int argc, VALUE *argv, VALUE exc)
  {
      if (!NIL_P(ruby_verbose) && argc > 0) {
  	rb_io_puts(argc, argv, rb_stderr);
      }
      return Qnil;
  }
  
  #define MAX_BUG_REPORTERS 0x100
  
  static struct bug_reporters {
      void (*func)(FILE *out, void *data);
      void *data;
  } bug_reporters[MAX_BUG_REPORTERS];
  
  static int bug_reporters_size;
  
  int
  rb_bug_reporter_add(void (*func)(FILE *, void *), void *data)
  {
      struct bug_reporters *reporter;
      if (bug_reporters_size >= MAX_BUG_REPORTERS) {
  	return 0; /* failed to register */
      }
      reporter = &bug_reporters[bug_reporters_size++];
      reporter->func = func;
      reporter->data = data;
  
      return 1;
  }
  
  static void
  report_bug(const char *file, int line, const char *fmt, va_list args)
  {
      /* SIGSEGV handler might have a very small stack. Thus we need to use it carefully. */
      char buf[256];
      FILE *out = stderr;
      int len = err_position_0(buf, 256, file, line);
  
      if ((ssize_t)fwrite(buf, 1, len, out) == (ssize_t)len ||
  	(ssize_t)fwrite(buf, 1, len, (out = stdout)) == (ssize_t)len) {
  
  	fputs("[BUG] ", out);
  	vsnprintf(buf, 256, fmt, args);
  	fputs(buf, out);
  	snprintf(buf, 256, "\n%s\n\n", ruby_description);
  	fputs(buf, out);
  
  	rb_vm_bugreport();
  
  	/* call additional bug reporters */
  	{
  	    int i;
  	    for (i=0; i<bug_reporters_size; i++) {
  		struct bug_reporters *reporter = &bug_reporters[i];
  		(*reporter->func)(out, reporter->data);
  	    }
  	}
  	fprintf(out, REPORTBUG_MSG);
      }
  }
  
  void
  rb_bug(const char *fmt, ...)
  {
      va_list args;
      const char *file = NULL;
      int line = 0;
  
      if (GET_THREAD()) {
  	file = rb_sourcefile();
  	line = rb_sourceline();
      }
  
      va_start(args, fmt);
      report_bug(file, line, fmt, args);
      va_end(args);
  
  #if defined(_WIN32) && defined(RUBY_MSVCRT_VERSION) && RUBY_MSVCRT_VERSION >= 80
      _set_abort_behavior( 0, _CALL_REPORTFAULT);
  #endif
  
      abort();
  }
  
  void
  rb_bug_errno(const char *mesg, int errno_arg)
  {
      if (errno_arg == 0)
          rb_bug("%s: errno == 0 (NOERROR)", mesg);
      else {
          const char *errno_str = rb_strerrno(errno_arg);
          if (errno_str)
              rb_bug("%s: %s (%s)", mesg, strerror(errno_arg), errno_str);
          else
              rb_bug("%s: %s (%d)", mesg, strerror(errno_arg), errno_arg);
      }
  }
  
  /*
   * this is safe to call inside signal handler and timer thread
   * (which isn't a Ruby Thread object)
   */
  #define write_or_abort(fd, str, len) (write((fd), (str), (len)) < 0 ? abort() : (void)0)
  #define WRITE_CONST(fd,str) write_or_abort((fd),(str),sizeof(str) - 1)
  
  void
  rb_async_bug_errno(const char *mesg, int errno_arg)
  {
      WRITE_CONST(2, "[ASYNC BUG] ");
      write_or_abort(2, mesg, strlen(mesg));
      WRITE_CONST(2, "\n");
  
      if (errno_arg == 0) {
  	WRITE_CONST(2, "errno == 0 (NOERROR)\n");
      }
      else {
  	const char *errno_str = rb_strerrno(errno_arg);
  
  	if (!errno_str)
  	    errno_str = "undefined errno";
  	write_or_abort(2, errno_str, strlen(errno_str));
      }
      WRITE_CONST(2, "\n\n");
      write_or_abort(2, ruby_description, strlen(ruby_description));
      WRITE_CONST(2, "\n\n");
      WRITE_CONST(2, REPORTBUG_MSG);
      abort();
  }
  
  void
  rb_compile_bug(const char *file, int line, const char *fmt, ...)
  {
      va_list args;
  
      va_start(args, fmt);
      report_bug(file, line, fmt, args);
      va_end(args);
  
      abort();
  }
  
  static const char builtin_types[][10] = {
      "", 			/* 0x00, */
      "Object",
      "Class",
      "Module",
      "Float",
      "String",
      "Regexp",
      "Array",
      "Hash",
      "Struct",
      "Bignum",
      "File",
      "Data",			/* internal use: wrapped C pointers */
      "MatchData",		/* data of $~ */
      "Complex",
      "Rational",
      "",				/* 0x10 */
      "nil",
      "true",
      "false",
      "Symbol",			/* :symbol */
      "Fixnum",
      "",				/* 0x16 */
      "",				/* 0x17 */
      "",				/* 0x18 */
      "",				/* 0x19 */
      "",				/* 0x1a */
      "undef",			/* internal use: #undef; should not happen */
      "Node",			/* internal use: syntax tree node */
      "iClass",			/* internal use: mixed-in module holder */
  };
  
  const char *
  rb_builtin_type_name(int t)
  {
      const char *name;
      if ((unsigned int)t >= numberof(builtin_types)) return 0;
      name = builtin_types[t];
      if (*name) return name;
      return 0;
  }
  
  #define builtin_class_name rb_builtin_class_name
  const char *
  rb_builtin_class_name(VALUE x)
  {
      const char *etype;
  
      if (NIL_P(x)) {
  	etype = "nil";
      }
      else if (FIXNUM_P(x)) {
  	etype = "Fixnum";
      }
      else if (SYMBOL_P(x)) {
  	etype = "Symbol";
      }
      else if (RB_TYPE_P(x, T_TRUE)) {
  	etype = "true";
      }
      else if (RB_TYPE_P(x, T_FALSE)) {
  	etype = "false";
      }
      else {
  	etype = rb_obj_classname(x);
      }
      return etype;
  }
  
  void
  rb_check_type(VALUE x, int t)
  {
      int xt;
  
      if (x == Qundef) {
  	rb_bug("undef leaked to the Ruby space");
      }
  
      xt = TYPE(x);
      if (xt != t || (xt == T_DATA && RTYPEDDATA_P(x))) {
  	const char *tname = rb_builtin_type_name(t);
  	if (tname) {
  	    rb_raise(rb_eTypeError, "wrong argument type %s (expected %s)",
  		     builtin_class_name(x), tname);
  	}
  	if (xt > T_MASK && xt <= 0x3f) {
  	    rb_fatal("unknown type 0x%x (0x%x given, probably comes from extension library for ruby 1.8)", t, xt);
  	}
  	rb_bug("unknown type 0x%x (0x%x given)", t, xt);
      }
  }
  
  int
  rb_typeddata_inherited_p(const rb_data_type_t *child, const rb_data_type_t *parent)
  {
      while (child) {
  	if (child == parent) return 1;
  	child = child->parent;
      }
      return 0;
  }
  
  int
  rb_typeddata_is_kind_of(VALUE obj, const rb_data_type_t *data_type)
  {
      if (!RB_TYPE_P(obj, T_DATA) ||
  	!RTYPEDDATA_P(obj) || !rb_typeddata_inherited_p(RTYPEDDATA_TYPE(obj), data_type)) {
  	return 0;
      }
      return 1;
  }
  
  void *
  rb_check_typeddata(VALUE obj, const rb_data_type_t *data_type)
  {
      const char *etype;
      static const char mesg[] = "wrong argument type %s (expected %s)";
  
      if (!RB_TYPE_P(obj, T_DATA)) {
  	etype = builtin_class_name(obj);
  	rb_raise(rb_eTypeError, mesg, etype, data_type->wrap_struct_name);
      }
      if (!RTYPEDDATA_P(obj)) {
  	etype = rb_obj_classname(obj);
  	rb_raise(rb_eTypeError, mesg, etype, data_type->wrap_struct_name);
      }
      else if (!rb_typeddata_inherited_p(RTYPEDDATA_TYPE(obj), data_type)) {
  	etype = RTYPEDDATA_TYPE(obj)->wrap_struct_name;
  	rb_raise(rb_eTypeError, mesg, etype, data_type->wrap_struct_name);
      }
      return DATA_PTR(obj);
  }
  
  /* exception classes */
  VALUE rb_eException;
  VALUE rb_eSystemExit;
  VALUE rb_eInterrupt;
  VALUE rb_eSignal;
  VALUE rb_eFatal;
  VALUE rb_eStandardError;
  VALUE rb_eRuntimeError;
  VALUE rb_eTypeError;
  VALUE rb_eArgError;
  VALUE rb_eIndexError;
  VALUE rb_eKeyError;
  VALUE rb_eRangeError;
  VALUE rb_eNameError;
  VALUE rb_eEncodingError;
  VALUE rb_eEncCompatError;
  VALUE rb_eNoMethodError;
  VALUE rb_eSecurityError;
  VALUE rb_eNotImpError;
  VALUE rb_eNoMemError;
  VALUE rb_cNameErrorMesg;
  
  VALUE rb_eScriptError;
  VALUE rb_eSyntaxError;
  VALUE rb_eLoadError;
  
  VALUE rb_eSystemCallError;
  VALUE rb_mErrno;
  static VALUE rb_eNOERROR;
  
  #undef rb_exc_new_cstr
  
  VALUE
  rb_exc_new(VALUE etype, const char *ptr, long len)
  {
      return rb_funcall(etype, rb_intern("new"), 1, rb_str_new(ptr, len));
  }
  
  VALUE
  rb_exc_new_cstr(VALUE etype, const char *s)
  {
      return rb_exc_new(etype, s, strlen(s));
  }
  
  VALUE
  rb_exc_new_str(VALUE etype, VALUE str)
  {
      StringValue(str);
      return rb_funcall(etype, rb_intern("new"), 1, str);
  }
  
  /*
   * call-seq:
   *    Exception.new(msg = nil)   ->  exception
   *
   *  Construct a new Exception object, optionally passing in
   *  a message.
   */
  
  static VALUE
  exc_initialize(int argc, VALUE *argv, VALUE exc)
  {
      VALUE arg;
  
      rb_scan_args(argc, argv, "01", &arg);
      rb_iv_set(exc, "mesg", arg);
      rb_iv_set(exc, "bt", Qnil);
  
      return exc;
  }
  
  /*
   *  Document-method: exception
   *
   *  call-seq:
   *     exc.exception(string)  ->  an_exception or exc
   *
   *  With no argument, or if the argument is the same as the receiver,
   *  return the receiver. Otherwise, create a new
   *  exception object of the same class as the receiver, but with a
   *  message equal to <code>string.to_str</code>.
   *
   */
  
  static VALUE
  exc_exception(int argc, VALUE *argv, VALUE self)
  {
      VALUE exc;
  
      if (argc == 0) return self;
      if (argc == 1 && self == argv[0]) return self;
      exc = rb_obj_clone(self);
      exc_initialize(argc, argv, exc);
  
      return exc;
  }
  
  /*
   * call-seq:
   *   exception.to_s   ->  string
   *
   * Returns exception's message (or the name of the exception if
   * no message is set).
   */
  
  static VALUE
  exc_to_s(VALUE exc)
  {
      VALUE mesg = rb_attr_get(exc, rb_intern("mesg"));
  
      if (NIL_P(mesg)) return rb_class_name(CLASS_OF(exc));
      return rb_String(mesg);
  }
  
  /*
   * call-seq:
   *   exception.message   ->  string
   *
   * Returns the result of invoking <code>exception.to_s</code>.
   * Normally this returns the exception's message or name. By
   * supplying a to_str method, exceptions are agreeing to
   * be used where Strings are expected.
   */
  
  static VALUE
  exc_message(VALUE exc)
  {
      return rb_funcall(exc, rb_intern("to_s"), 0, 0);
  }
  
  /*
   * call-seq:
   *   exception.inspect   -> string
   *
   * Return this exception's class name and message
   */
  
  static VALUE
  exc_inspect(VALUE exc)
  {
      VALUE str, klass;
  
      klass = CLASS_OF(exc);
      exc = rb_obj_as_string(exc);
      if (RSTRING_LEN(exc) == 0) {
  	return rb_str_dup(rb_class_name(klass));
      }
  
      str = rb_str_buf_new2("#<");
      klass = rb_class_name(klass);
      rb_str_buf_append(str, klass);
      rb_str_buf_cat(str, ": ", 2);
      rb_str_buf_append(str, exc);
      rb_str_buf_cat(str, ">", 1);
  
      return str;
  }
  
  /*
   *  call-seq:
   *     exception.backtrace    -> array
   *
   *  Returns any backtrace associated with the exception. The backtrace
   *  is an array of strings, each containing either ``filename:lineNo: in
   *  `method''' or ``filename:lineNo.''
   *
   *     def a
   *       raise "boom"
   *     end
   *
   *     def b
   *       a()
   *     end
   *
   *     begin
   *       b()
   *     rescue => detail
   *       print detail.backtrace.join("\n")
   *     end
   *
   *  <em>produces:</em>
   *
   *     prog.rb:2:in `a'
   *     prog.rb:6:in `b'
   *     prog.rb:10
  */
  
  static VALUE
  exc_backtrace(VALUE exc)
  {
      ID bt;
      VALUE obj;
  
      CONST_ID(bt, "bt");
      obj = rb_attr_get(exc, bt);
  
      if (rb_backtrace_p(obj)) {
  	obj = rb_backtrace_to_str_ary(obj);
  	/* rb_iv_set(exc, "bt", obj); */
      }
  
      return obj;
  }
  
  /*
   *  call-seq:
   *     exception.backtrace_locations    -> array
   *
   *  Returns any backtrace associated with the exception. This method is
   *  similar to Exception#backtrace, but the backtrace is an array of
   *   Thread::Backtrace::Location.
   *
   *  Now, this method is not affected by Exception#set_backtrace().
   */
  static VALUE
  exc_backtrace_locations(VALUE exc)
  {
      ID bt_locations;
      VALUE obj;
  
      CONST_ID(bt_locations, "bt_locations");
      obj = rb_attr_get(exc, bt_locations);
      if (!NIL_P(obj)) {
  	obj = rb_backtrace_to_location_ary(obj);
      }
      return obj;
  }
  
  VALUE
  rb_check_backtrace(VALUE bt)
  {
      long i;
      static const char err[] = "backtrace must be Array of String";
  
      if (!NIL_P(bt)) {
  	if (RB_TYPE_P(bt, T_STRING)) return rb_ary_new3(1, bt);
  	if (rb_backtrace_p(bt)) return bt;
  	if (!RB_TYPE_P(bt, T_ARRAY)) {
  	    rb_raise(rb_eTypeError, err);
  	}
  	for (i=0;i<RARRAY_LEN(bt);i++) {
  	    VALUE e = RARRAY_AREF(bt, i);
  	    if (!RB_TYPE_P(e, T_STRING)) {
  		rb_raise(rb_eTypeError, err);
  	    }
  	}
      }
      return bt;
  }
  
  /*
   *  call-seq:
   *     exc.set_backtrace(backtrace)   ->  array
   *
   *  Sets the backtrace information associated with +exc+. The +backtrace+ must
   *  be an array of String objects or a single String in the format described
   *  in Exception#backtrace.
   *
   */
  
  static VALUE
  exc_set_backtrace(VALUE exc, VALUE bt)
  {
      return rb_iv_set(exc, "bt", rb_check_backtrace(bt));
  }
  
  VALUE
  rb_exc_set_backtrace(VALUE exc, VALUE bt)
  {
      return exc_set_backtrace(exc, bt);
  }
  
  VALUE
  exc_cause(VALUE exc)
  {
      ID id_cause;
      CONST_ID(id_cause, "cause");
      return rb_attr_get(exc, id_cause);
  }
  
  static VALUE
  try_convert_to_exception(VALUE obj)
  {
      ID id_exception;
      CONST_ID(id_exception, "exception");
      return rb_check_funcall(obj, id_exception, 0, 0);
  }
  
  /*
   *  call-seq:
   *     exc == obj   -> true or false
   *
   *  Equality---If <i>obj</i> is not an <code>Exception</code>, returns
   *  <code>false</code>. Otherwise, returns <code>true</code> if <i>exc</i> and
   *  <i>obj</i> share same class, messages, and backtrace.
   */
  
  static VALUE
  exc_equal(VALUE exc, VALUE obj)
  {
      VALUE mesg, backtrace;
      ID id_mesg;
  
      if (exc == obj) return Qtrue;
      CONST_ID(id_mesg, "mesg");
  
      if (rb_obj_class(exc) != rb_obj_class(obj)) {
  	int status = 0;
  	ID id_message, id_backtrace;
  	CONST_ID(id_message, "message");
  	CONST_ID(id_backtrace, "backtrace");
  
  	obj = rb_protect(try_convert_to_exception, obj, &status);
  	if (status || obj == Qundef) {
  	    rb_set_errinfo(Qnil);
  	    return Qfalse;
  	}
  	if (rb_obj_class(exc) != rb_obj_class(obj)) return Qfalse;
  	mesg = rb_check_funcall(obj, id_message, 0, 0);
  	if (mesg == Qundef) return Qfalse;
  	backtrace = rb_check_funcall(obj, id_backtrace, 0, 0);
  	if (backtrace == Qundef) return Qfalse;
      }
      else {
  	mesg = rb_attr_get(obj, id_mesg);
  	backtrace = exc_backtrace(obj);
      }
  
      if (!rb_equal(rb_attr_get(exc, id_mesg), mesg))
  	return Qfalse;
      if (!rb_equal(exc_backtrace(exc), backtrace))
  	return Qfalse;
      return Qtrue;
  }
  
  /*
   * call-seq:
   *   SystemExit.new              -> system_exit
   *   SystemExit.new(status)      -> system_exit
   *   SystemExit.new(status, msg) -> system_exit
   *   SystemExit.new(msg)         -> system_exit
   *
   * Create a new +SystemExit+ exception with the given status and message.
   * Status is true, false, or an integer.
   * If status is not given, true is used.
   */
  
  static VALUE
  exit_initialize(int argc, VALUE *argv, VALUE exc)
  {
      VALUE status;
      if (argc > 0) {
  	status = *argv;
  
  	switch (status) {
  	  case Qtrue:
  	    status = INT2FIX(EXIT_SUCCESS);
  	    ++argv;
  	    --argc;
  	    break;
  	  case Qfalse:
  	    status = INT2FIX(EXIT_FAILURE);
  	    ++argv;
  	    --argc;
  	    break;
  	  default:
  	    status = rb_check_to_int(status);
  	    if (NIL_P(status)) {
  		status = INT2FIX(EXIT_SUCCESS);
  	    }
  	    else {
  #if EXIT_SUCCESS != 0
  		if (status == INT2FIX(0))
  		    status = INT2FIX(EXIT_SUCCESS);
  #endif
  		++argv;
  		--argc;
  	    }
  	    break;
  	}
      }
      else {
  	status = INT2FIX(EXIT_SUCCESS);
      }
      rb_call_super(argc, argv);
      rb_iv_set(exc, "status", status);
      return exc;
  }
  
  
  /*
   * call-seq:
   *   system_exit.status   -> fixnum
   *
   * Return the status value associated with this system exit.
   */
  
  static VALUE
  exit_status(VALUE exc)
  {
      return rb_attr_get(exc, rb_intern("status"));
  }
  
  
  /*
   * call-seq:
   *   system_exit.success?  -> true or false
   *
   * Returns +true+ if exiting successful, +false+ if not.
   */
  
  static VALUE
  exit_success_p(VALUE exc)
  {
      VALUE status_val = rb_attr_get(exc, rb_intern("status"));
      int status;
  
      if (NIL_P(status_val))
  	return Qtrue;
      status = NUM2INT(status_val);
      if (WIFEXITED(status) && WEXITSTATUS(status) == EXIT_SUCCESS)
  	return Qtrue;
  
      return Qfalse;
  }
  
  void
  rb_name_error(ID id, const char *fmt, ...)
  {
      VALUE exc, argv[2];
      va_list args;
  
      va_start(args, fmt);
      argv[0] = rb_vsprintf(fmt, args);
      va_end(args);
  
      argv[1] = ID2SYM(id);
      exc = rb_class_new_instance(2, argv, rb_eNameError);
      rb_exc_raise(exc);
  }
  
  void
  rb_name_error_str(VALUE str, const char *fmt, ...)
  {
      VALUE exc, argv[2];
      va_list args;
  
      va_start(args, fmt);
      argv[0] = rb_vsprintf(fmt, args);
      va_end(args);
  
      argv[1] = str;
      exc = rb_class_new_instance(2, argv, rb_eNameError);
      rb_exc_raise(exc);
  }
  
  /*
   * call-seq:
   *   NameError.new(msg [, name])  -> name_error
   *
   * Construct a new NameError exception. If given the <i>name</i>
   * parameter may subsequently be examined using the <code>NameError.name</code>
   * method.
   */
  
  static VALUE
  name_err_initialize(int argc, VALUE *argv, VALUE self)
  {
      VALUE name;
  
      name = (argc > 1) ? argv[--argc] : Qnil;
      rb_call_super(argc, argv);
      rb_iv_set(self, "name", name);
      return self;
  }
  
  /*
   *  call-seq:
   *    name_error.name    ->  string or nil
   *
   *  Return the name associated with this NameError exception.
   */
  
  static VALUE
  name_err_name(VALUE self)
  {
      return rb_attr_get(self, rb_intern("name"));
  }
  
  /*
   * call-seq:
   *   NoMethodError.new(msg, name [, args])  -> no_method_error
   *
   * Construct a NoMethodError exception for a method of the given name
   * called with the given arguments. The name may be accessed using
   * the <code>#name</code> method on the resulting object, and the
   * arguments using the <code>#args</code> method.
   */
  
  static VALUE
  nometh_err_initialize(int argc, VALUE *argv, VALUE self)
  {
      VALUE args = (argc > 2) ? argv[--argc] : Qnil;
      name_err_initialize(argc, argv, self);
      rb_iv_set(self, "args", args);
      return self;
  }
  
  /* :nodoc: */
  #define NAME_ERR_MESG_COUNT 3
  
  static void
  name_err_mesg_mark(void *p)
  {
      VALUE *ptr = p;
      rb_gc_mark_locations(ptr, ptr+NAME_ERR_MESG_COUNT);
  }
  
  #define name_err_mesg_free RUBY_TYPED_DEFAULT_FREE
  
  static size_t
  name_err_mesg_memsize(const void *p)
  {
      return p ? (NAME_ERR_MESG_COUNT * sizeof(VALUE)) : 0;
  }
  
  static const rb_data_type_t name_err_mesg_data_type = {
      "name_err_mesg",
      {
  	name_err_mesg_mark,
  	name_err_mesg_free,
  	name_err_mesg_memsize,
      },
      NULL, NULL, RUBY_TYPED_FREE_IMMEDIATELY
  };
  
  /* :nodoc: */
  VALUE
  rb_name_err_mesg_new(VALUE obj, VALUE mesg, VALUE recv, VALUE method)
  {
      VALUE *ptr = ALLOC_N(VALUE, NAME_ERR_MESG_COUNT);
      VALUE result;
  
      ptr[0] = mesg;
      ptr[1] = recv;
      ptr[2] = method;
      result = TypedData_Wrap_Struct(rb_cNameErrorMesg, &name_err_mesg_data_type, ptr);
      RB_GC_GUARD(mesg);
      RB_GC_GUARD(recv);
      RB_GC_GUARD(method);
      return result;
  }
  
  /* :nodoc: */
  static VALUE
  name_err_mesg_equal(VALUE obj1, VALUE obj2)
  {
      VALUE *ptr1, *ptr2;
      int i;
  
      if (obj1 == obj2) return Qtrue;
      if (rb_obj_class(obj2) != rb_cNameErrorMesg)
  	return Qfalse;
  
      TypedData_Get_Struct(obj1, VALUE, &name_err_mesg_data_type, ptr1);
      TypedData_Get_Struct(obj2, VALUE, &name_err_mesg_data_type, ptr2);
      for (i=0; i<NAME_ERR_MESG_COUNT; i++) {
  	if (!rb_equal(ptr1[i], ptr2[i]))
  	    return Qfalse;
      }
      return Qtrue;
  }
  
  /* :nodoc: */
  static VALUE
  name_err_mesg_to_str(VALUE obj)
  {
      VALUE *ptr, mesg;
      TypedData_Get_Struct(obj, VALUE, &name_err_mesg_data_type, ptr);
  
      mesg = ptr[0];
      if (NIL_P(mesg)) return Qnil;
      else {
  	const char *desc = 0;
  	VALUE d = 0, args[NAME_ERR_MESG_COUNT];
  	int state = 0;
  
  	obj = ptr[1];
  	switch (obj) {
  	  case Qnil:
  	    desc = "nil";
  	    break;
  	  case Qtrue:
  	    desc = "true";
  	    break;
  	  case Qfalse:
  	    desc = "false";
  	    break;
  	  default:
  	    d = rb_protect(rb_inspect, obj, &state);
  	    if (state)
  		rb_set_errinfo(Qnil);
  	    if (NIL_P(d) || RSTRING_LEN(d) > 65) {
  		d = rb_any_to_s(obj);
  	    }
  	    desc = RSTRING_PTR(d);
  	    break;
  	}
  	if (desc && desc[0] != '#') {
  	    d = d ? rb_str_dup(d) : rb_str_new2(desc);
  	    rb_str_cat2(d, ":");
  	    rb_str_append(d, rb_class_name(CLASS_OF(obj)));
  	}
  	args[0] = mesg;
  	args[1] = ptr[2];
  	args[2] = d;
  	mesg = rb_f_sprintf(NAME_ERR_MESG_COUNT, args);
      }
      return mesg;
  }
  
  /* :nodoc: */
  static VALUE
  name_err_mesg_dump(VALUE obj, VALUE limit)
  {
      return name_err_mesg_to_str(obj);
  }
  
  /* :nodoc: */
  static VALUE
  name_err_mesg_load(VALUE klass, VALUE str)
  {
      return str;
  }
  
  /*
   * call-seq:
   *   no_method_error.args  -> obj
   *
   * Return the arguments passed in as the third parameter to
   * the constructor.
   */
  
  static VALUE
  nometh_err_args(VALUE self)
  {
      return rb_attr_get(self, rb_intern("args"));
  }
  
  void
  rb_invalid_str(const char *str, const char *type)
  {
      VALUE s = rb_str_new2(str);
  
      rb_raise(rb_eArgError, "invalid value for %s: %+"PRIsVALUE, type, s);
  }
  
  /*
   *  Document-module: Errno
   *
   *  Ruby exception objects are subclasses of <code>Exception</code>.
   *  However, operating systems typically report errors using plain
   *  integers. Module <code>Errno</code> is created dynamically to map
   *  these operating system errors to Ruby classes, with each error
   *  number generating its own subclass of <code>SystemCallError</code>.
   *  As the subclass is created in module <code>Errno</code>, its name
   *  will start <code>Errno::</code>.
   *
   *  The names of the <code>Errno::</code> classes depend on
   *  the environment in which Ruby runs. On a typical Unix or Windows
   *  platform, there are <code>Errno</code> classes such as
   *  <code>Errno::EACCES</code>, <code>Errno::EAGAIN</code>,
   *  <code>Errno::EINTR</code>, and so on.
   *
   *  The integer operating system error number corresponding to a
   *  particular error is available as the class constant
   *  <code>Errno::</code><em>error</em><code>::Errno</code>.
   *
   *     Errno::EACCES::Errno   #=> 13
   *     Errno::EAGAIN::Errno   #=> 11
   *     Errno::EINTR::Errno    #=> 4
   *
   *  The full list of operating system errors on your particular platform
   *  are available as the constants of <code>Errno</code>.
   *
   *     Errno.constants   #=> :E2BIG, :EACCES, :EADDRINUSE, :EADDRNOTAVAIL, ...
   */
  
  static st_table *syserr_tbl;
  
  static VALUE
  set_syserr(int n, const char *name)
  {
      st_data_t error;
  
      if (!st_lookup(syserr_tbl, n, &error)) {
  	error = rb_define_class_under(rb_mErrno, name, rb_eSystemCallError);
  
  	/* capture nonblock errnos for WaitReadable/WaitWritable subclasses */
  	switch (n) {
  	    case EAGAIN:
  	        rb_eEAGAIN = error;
  
  #if EAGAIN != EWOULDBLOCK
                  break;
  	    case EWOULDBLOCK:
  #endif
  
  		rb_eEWOULDBLOCK = error;
  		break;
  	    case EINPROGRESS:
  		rb_eEINPROGRESS = error;
  		break;
  	}
  
  	rb_define_const(error, "Errno", INT2NUM(n));
  	st_add_direct(syserr_tbl, n, error);
      }
      else {
  	rb_define_const(rb_mErrno, name, error);
      }
      return error;
  }
  
  static VALUE
  get_syserr(int n)
  {
      st_data_t error;
  
      if (!st_lookup(syserr_tbl, n, &error)) {
  	char name[8];	/* some Windows' errno have 5 digits. */
  
  	snprintf(name, sizeof(name), "E%03d", n);
  	error = set_syserr(n, name);
      }
      return error;
  }
  
  /*
   * call-seq:
   *   SystemCallError.new(msg, errno)  -> system_call_error_subclass
   *
   * If _errno_ corresponds to a known system error code, constructs
   * the appropriate <code>Errno</code> class for that error, otherwise
   * constructs a generic <code>SystemCallError</code> object. The
   * error number is subsequently available via the <code>errno</code>
   * method.
   */
  
  static VALUE
  syserr_initialize(int argc, VALUE *argv, VALUE self)
  {
  #if !defined(_WIN32)
      char *strerror();
  #endif
      const char *err;
      VALUE mesg, error, func;
      VALUE klass = rb_obj_class(self);
  
      if (klass == rb_eSystemCallError) {
  	st_data_t data = (st_data_t)klass;
  	rb_scan_args(argc, argv, "12", &mesg, &error, &func);
  	if (argc == 1 && FIXNUM_P(mesg)) {
  	    error = mesg; mesg = Qnil;
  	}
  	if (!NIL_P(error) && st_lookup(syserr_tbl, NUM2LONG(error), &data)) {
  	    klass = (VALUE)data;
  	    /* change class */
  	    if (!RB_TYPE_P(self, T_OBJECT)) { /* insurance to avoid type crash */
  		rb_raise(rb_eTypeError, "invalid instance type");
  	    }
  	    RBASIC_SET_CLASS(self, klass);
  	}
      }
      else {
  	rb_scan_args(argc, argv, "02", &mesg, &func);
  	error = rb_const_get(klass, rb_intern("Errno"));
      }
      if (!NIL_P(error)) err = strerror(NUM2INT(error));
      else err = "unknown error";
      if (!NIL_P(mesg)) {
  	rb_encoding *le = rb_locale_encoding();
  	VALUE str = StringValue(mesg);
  	rb_encoding *me = rb_enc_get(mesg);
  
  	if (NIL_P(func))
  	    mesg = rb_sprintf("%s - %"PRIsVALUE, err, mesg);
  	else
  	    mesg = rb_sprintf("%s @ %"PRIsVALUE" - %"PRIsVALUE, err, func, mesg);
  	if (le != me && rb_enc_asciicompat(me)) {
  	    le = me;
  	}/* else assume err is non ASCII string. */
  	OBJ_INFECT(mesg, str);
  	rb_enc_associate(mesg, le);
      }
      else {
  	mesg = rb_str_new2(err);
  	rb_enc_associate(mesg, rb_locale_encoding());
      }
      rb_call_super(1, &mesg);
      rb_iv_set(self, "errno", error);
      return self;
  }
  
  /*
   * call-seq:
   *   system_call_error.errno   -> fixnum
   *
   * Return this SystemCallError's error number.
   */
  
  static VALUE
  syserr_errno(VALUE self)
  {
      return rb_attr_get(self, rb_intern("errno"));
  }
  
  /*
   * call-seq:
   *   system_call_error === other  -> true or false
   *
   * Return +true+ if the receiver is a generic +SystemCallError+, or
   * if the error numbers +self+ and _other_ are the same.
   */
  
  static VALUE
  syserr_eqq(VALUE self, VALUE exc)
  {
      VALUE num, e;
      ID en;
  
      CONST_ID(en, "errno");
  
      if (!rb_obj_is_kind_of(exc, rb_eSystemCallError)) {
  	if (!rb_respond_to(exc, en)) return Qfalse;
      }
      else if (self == rb_eSystemCallError) return Qtrue;
  
      num = rb_attr_get(exc, rb_intern("errno"));
      if (NIL_P(num)) {
  	num = rb_funcall(exc, en, 0, 0);
      }
      e = rb_const_get(self, rb_intern("Errno"));
      if (FIXNUM_P(num) ? num == e : rb_equal(num, e))
  	return Qtrue;
      return Qfalse;
  }
  
  
  /*
   *  Document-class: StandardError
   *
   *  The most standard error types are subclasses of StandardError. A
   *  rescue clause without an explicit Exception class will rescue all
   *  StandardErrors (and only those).
   *
   *     def foo
   *       raise "Oups"
   *     end
   *     foo rescue "Hello"   #=> "Hello"
   *
   *  On the other hand:
   *
   *     require 'does/not/exist' rescue "Hi"
   *
   *  <em>raises the exception:</em>
   *
   *     LoadError: no such file to load -- does/not/exist
   *
   */
  
  /*
   *  Document-class: SystemExit
   *
   *  Raised by +exit+ to initiate the termination of the script.
   */
  
  /*
   *  Document-class: SignalException
   *
   *  Raised when a signal is received.
   *
   *     begin
   *       Process.kill('HUP',Process.pid)
   *       sleep # wait for receiver to handle signal sent by Process.kill
   *     rescue SignalException => e
   *       puts "received Exception #{e}"
   *     end
   *
   *  <em>produces:</em>
   *
   *     received Exception SIGHUP
   */
  
  /*
   *  Document-class: Interrupt
   *
   *  Raised with the interrupt signal is received, typically because the
   *  user pressed on Control-C (on most posix platforms). As such, it is a
   *  subclass of +SignalException+.
   *
   *     begin
   *       puts "Press ctrl-C when you get bored"
   *       loop {}
   *     rescue Interrupt => e
   *       puts "Note: You will typically use Signal.trap instead."
   *     end
   *
   *  <em>produces:</em>
   *
   *     Press ctrl-C when you get bored
   *
   *  <em>then waits until it is interrupted with Control-C and then prints:</em>
   *
   *     Note: You will typically use Signal.trap instead.
   */
  
  /*
   *  Document-class: TypeError
   *
   *  Raised when encountering an object that is not of the expected type.
   *
   *     [1, 2, 3].first("two")
   *
   *  <em>raises the exception:</em>
   *
   *     TypeError: no implicit conversion of String into Integer
   *
   */
  
  /*
   *  Document-class: ArgumentError
   *
   *  Raised when the arguments are wrong and there isn't a more specific
   *  Exception class.
   *
   *  Ex: passing the wrong number of arguments
   *
   *     [1, 2, 3].first(4, 5)
   *
   *  <em>raises the exception:</em>
   *
   *     ArgumentError: wrong number of arguments (2 for 1)
   *
   *  Ex: passing an argument that is not acceptable:
   *
   *     [1, 2, 3].first(-4)
   *
   *  <em>raises the exception:</em>
   *
   *     ArgumentError: negative array size
   */
  
  /*
   *  Document-class: IndexError
   *
   *  Raised when the given index is invalid.
   *
   *     a = [:foo, :bar]
   *     a.fetch(0)   #=> :foo
   *     a[4]         #=> nil
   *     a.fetch(4)   #=> IndexError: index 4 outside of array bounds: -2...2
   *
   */
  
  /*
   *  Document-class: KeyError
   *
   *  Raised when the specified key is not found. It is a subclass of
   *  IndexError.
   *
   *     h = {"foo" => :bar}
   *     h.fetch("foo") #=> :bar
   *     h.fetch("baz") #=> KeyError: key not found: "baz"
   *
   */
  
  /*
   *  Document-class: RangeError
   *
   *  Raised when a given numerical value is out of range.
   *
   *     [1, 2, 3].drop(1 << 100)
   *
   *  <em>raises the exception:</em>
   *
   *     RangeError: bignum too big to convert into `long'
   */
  
  /*
   *  Document-class: ScriptError
   *
   *  ScriptError is the superclass for errors raised when a script
   *  can not be executed because of a +LoadError+,
   *  +NotImplementedError+ or a +SyntaxError+. Note these type of
   *  +ScriptErrors+ are not +StandardError+ and will not be
   *  rescued unless it is specified explicitly (or its ancestor
   *  +Exception+).
   */
  
  /*
   *  Document-class: SyntaxError
   *
   *  Raised when encountering Ruby code with an invalid syntax.
   *
   *     eval("1+1=2")
   *
   *  <em>raises the exception:</em>
   *
   *     SyntaxError: (eval):1: syntax error, unexpected '=', expecting $end
   */
  
  /*
   *  Document-class: LoadError
   *
   *  Raised when a file required (a Ruby script, extension library, ...)
   *  fails to load.
   *
   *     require 'this/file/does/not/exist'
   *
   *  <em>raises the exception:</em>
   *
   *     LoadError: no such file to load -- this/file/does/not/exist
   */
  
  /*
   *  Document-class: NotImplementedError
   *
   *  Raised when a feature is not implemented on the current platform. For
   *  example, methods depending on the +fsync+ or +fork+ system calls may
   *  raise this exception if the underlying operating system or Ruby
   *  runtime does not support them.
   *
   *  Note that if +fork+ raises a +NotImplementedError+, then
   *  <code>respond_to?(:fork)</code> returns +false+.
   */
  
  /*
   *  Document-class: NameError
   *
   *  Raised when a given name is invalid or undefined.
   *
   *     puts foo
   *
   *  <em>raises the exception:</em>
   *
   *     NameError: undefined local variable or method `foo' for main:Object
   *
   *  Since constant names must start with a capital:
   *
   *     Fixnum.const_set :answer, 42
   *
   *  <em>raises the exception:</em>
   *
   *     NameError: wrong constant name answer
   */
  
  /*
   *  Document-class: NoMethodError
   *
   *  Raised when a method is called on a receiver which doesn't have it
   *  defined and also fails to respond with +method_missing+.
   *
   *     "hello".to_ary
   *
   *  <em>raises the exception:</em>
   *
   *     NoMethodError: undefined method `to_ary' for "hello":String
   */
  
  /*
   *  Document-class: RuntimeError
   *
   *  A generic error class raised when an invalid operation is attempted.
   *
   *     [1, 2, 3].freeze << 4
   *
   *  <em>raises the exception:</em>
   *
   *     RuntimeError: can't modify frozen array
   *
   *  Kernel.raise will raise a RuntimeError if no Exception class is
   *  specified.
   *
   *     raise "ouch"
   *
   *  <em>raises the exception:</em>
   *
   *     RuntimeError: ouch
   */
  
  /*
   *  Document-class: SecurityError
   *
   *  Raised when attempting a potential unsafe operation, typically when
   *  the $SAFE level is raised above 0.
   *
   *     foo = "bar"
   *     proc = Proc.new do
   *       $SAFE = 3
   *       foo.untaint
   *     end
   *     proc.call
   *
   *  <em>raises the exception:</em>
   *
   *     SecurityError: Insecure: Insecure operation `untaint' at level 3
   */
  
  /*
   *  Document-class: NoMemoryError
   *
   *  Raised when memory allocation fails.
   */
  
  /*
   *  Document-class: SystemCallError
   *
   *  SystemCallError is the base class for all low-level
   *  platform-dependent errors.
   *
   *  The errors available on the current platform are subclasses of
   *  SystemCallError and are defined in the Errno module.
   *
   *     File.open("does/not/exist")
   *
   *  <em>raises the exception:</em>
   *
   *     Errno::ENOENT: No such file or directory - does/not/exist
   */
  
  /*
   * Document-class: EncodingError
   *
   * EncodingError is the base class for encoding errors.
   */
  
  /*
   *  Document-class: Encoding::CompatibilityError
   *
   *  Raised by Encoding and String methods when the source encoding is
   *  incompatible with the target encoding.
   */
  
  /*
   * Document-class: fatal
   *
   * fatal is an Exception that is raised when ruby has encountered a fatal
   * error and must exit.  You are not able to rescue fatal.
   */
  
  /*
   * Document-class: NameError::message
   * :nodoc:
   */
  
  /*
   *  Descendants of class Exception are used to communicate between
   *  Kernel#raise and +rescue+ statements in <code>begin ... end</code> blocks.
   *  Exception objects carry information about the exception -- its type (the
   *  exception's class name), an optional descriptive string, and optional
   *  traceback information.  Exception subclasses may add additional
   *  information like NameError#name.
   *
   *  Programs may make subclasses of Exception, typically of StandardError or
   *  RuntimeError, to provide custom classes and add additional information.
   *  See the subclass list below for defaults for +raise+ and +rescue+.
   *
   *  When an exception has been raised but not yet handled (in +rescue+,
   *  +ensure+, +at_exit+ and +END+ blocks) the global variable <code>$!</code>
   *  will contain the current exception and <code>$@</code> contains the
   *  current exception's backtrace.
   *
   *  It is recommended that a library should have one subclass of StandardError
   *  or RuntimeError and have specific exception types inherit from it.  This
   *  allows the user to rescue a generic exception type to catch all exceptions
   *  the library may raise even if future versions of the library add new
   *  exception subclasses.
   *
   *  For example:
   *
   *    class MyLibrary
   *      class Error < RuntimeError
   *      end
   *
   *      class WidgetError < Error
   *      end
   *
   *      class FrobError < Error
   *      end
   *
   *    end
   *
   *  To handle both WidgetError and FrobError the library user can rescue
   *  MyLibrary::Error.
   *
   *  The built-in subclasses of Exception are:
   *
   *  * NoMemoryError
   *  * ScriptError
   *    * LoadError
   *    * NotImplementedError
   *    * SyntaxError
   *  * SecurityError
   *  * SignalException
   *    * Interrupt
   *  * StandardError -- default for +rescue+
   *    * ArgumentError
   *    * EncodingError
   *    * FiberError
   *    * IOError
   *      * EOFError
   *    * IndexError
   *      * KeyError
   *      * StopIteration
   *    * LocalJumpError
   *    * NameError
   *      * NoMethodError
   *    * RangeError
   *      * FloatDomainError
   *    * RegexpError
   *    * RuntimeError -- default for +raise+
   *    * SystemCallError
   *      * Errno::*
   *    * ThreadError
   *    * TypeError
   *    * ZeroDivisionError
   *  * SystemExit
   *  * SystemStackError
   *  * fatal -- impossible to rescue
   */
  
  void
  Init_Exception(void)
  {
      rb_eException   = rb_define_class("Exception", rb_cObject);
      rb_define_singleton_method(rb_eException, "exception", rb_class_new_instance, -1);
      rb_define_method(rb_eException, "exception", exc_exception, -1);
      rb_define_method(rb_eException, "initialize", exc_initialize, -1);
      rb_define_method(rb_eException, "==", exc_equal, 1);
      rb_define_method(rb_eException, "to_s", exc_to_s, 0);
      rb_define_method(rb_eException, "message", exc_message, 0);
      rb_define_method(rb_eException, "inspect", exc_inspect, 0);
      rb_define_method(rb_eException, "backtrace", exc_backtrace, 0);
      rb_define_method(rb_eException, "backtrace_locations", exc_backtrace_locations, 0);
      rb_define_method(rb_eException, "set_backtrace", exc_set_backtrace, 1);
      rb_define_method(rb_eException, "cause", exc_cause, 0);
  
      rb_eSystemExit  = rb_define_class("SystemExit", rb_eException);
      rb_define_method(rb_eSystemExit, "initialize", exit_initialize, -1);
      rb_define_method(rb_eSystemExit, "status", exit_status, 0);
      rb_define_method(rb_eSystemExit, "success?", exit_success_p, 0);
  
      rb_eFatal  	    = rb_define_class("fatal", rb_eException);
      rb_eSignal      = rb_define_class("SignalException", rb_eException);
      rb_eInterrupt   = rb_define_class("Interrupt", rb_eSignal);
  
      rb_eStandardError = rb_define_class("StandardError", rb_eException);
      rb_eTypeError     = rb_define_class("TypeError", rb_eStandardError);
      rb_eArgError      = rb_define_class("ArgumentError", rb_eStandardError);
      rb_eIndexError    = rb_define_class("IndexError", rb_eStandardError);
      rb_eKeyError      = rb_define_class("KeyError", rb_eIndexError);
      rb_eRangeError    = rb_define_class("RangeError", rb_eStandardError);
  
      rb_eScriptError = rb_define_class("ScriptError", rb_eException);
      rb_eSyntaxError = rb_define_class("SyntaxError", rb_eScriptError);
  
      rb_eLoadError   = rb_define_class("LoadError", rb_eScriptError);
      /* the path failed to load */
      rb_attr(rb_eLoadError, rb_intern("path"), 1, 0, Qfalse);
  
      rb_eNotImpError = rb_define_class("NotImplementedError", rb_eScriptError);
  
      rb_eNameError     = rb_define_class("NameError", rb_eStandardError);
      rb_define_method(rb_eNameError, "initialize", name_err_initialize, -1);
      rb_define_method(rb_eNameError, "name", name_err_name, 0);
      rb_cNameErrorMesg = rb_define_class_under(rb_eNameError, "message", rb_cData);
      rb_define_singleton_method(rb_cNameErrorMesg, "!", rb_name_err_mesg_new, NAME_ERR_MESG_COUNT);
      rb_define_method(rb_cNameErrorMesg, "==", name_err_mesg_equal, 1);
      rb_define_method(rb_cNameErrorMesg, "to_str", name_err_mesg_to_str, 0);
      rb_define_method(rb_cNameErrorMesg, "_dump", name_err_mesg_dump, 1);
      rb_define_singleton_method(rb_cNameErrorMesg, "_load", name_err_mesg_load, 1);
      rb_eNoMethodError = rb_define_class("NoMethodError", rb_eNameError);
      rb_define_method(rb_eNoMethodError, "initialize", nometh_err_initialize, -1);
      rb_define_method(rb_eNoMethodError, "args", nometh_err_args, 0);
  
      rb_eRuntimeError = rb_define_class("RuntimeError", rb_eStandardError);
      rb_eSecurityError = rb_define_class("SecurityError", rb_eException);
      rb_eNoMemError = rb_define_class("NoMemoryError", rb_eException);
      rb_eEncodingError = rb_define_class("EncodingError", rb_eStandardError);
      rb_eEncCompatError = rb_define_class_under(rb_cEncoding, "CompatibilityError", rb_eEncodingError);
  
      syserr_tbl = st_init_numtable();
      rb_eSystemCallError = rb_define_class("SystemCallError", rb_eStandardError);
      rb_define_method(rb_eSystemCallError, "initialize", syserr_initialize, -1);
      rb_define_method(rb_eSystemCallError, "errno", syserr_errno, 0);
      rb_define_singleton_method(rb_eSystemCallError, "===", syserr_eqq, 1);
  
      rb_mErrno = rb_define_module("Errno");
  
      rb_define_global_function("warn", rb_warn_m, -1);
  }
  
  void
  rb_enc_raise(rb_encoding *enc, VALUE exc, const char *fmt, ...)
  {
      va_list args;
      VALUE mesg;
  
      va_start(args, fmt);
      mesg = rb_enc_vsprintf(enc, fmt, args);
      va_end(args);
  
      rb_exc_raise(rb_exc_new3(exc, mesg));
  }
  
  void
  rb_raise(VALUE exc, const char *fmt, ...)
  {
      va_list args;
      VALUE mesg;
  
      va_start(args, fmt);
      mesg = rb_vsprintf(fmt, args);
      va_end(args);
      rb_exc_raise(rb_exc_new3(exc, mesg));
  }
  
  NORETURN(static void raise_loaderror(VALUE path, VALUE mesg));
  
  static void
  raise_loaderror(VALUE path, VALUE mesg)
  {
      VALUE err = rb_exc_new3(rb_eLoadError, mesg);
      rb_ivar_set(err, rb_intern("@path"), path);
      rb_exc_raise(err);
  }
  
  void
  rb_loaderror(const char *fmt, ...)
  {
      va_list args;
      VALUE mesg;
  
      va_start(args, fmt);
      mesg = rb_enc_vsprintf(rb_locale_encoding(), fmt, args);
      va_end(args);
      raise_loaderror(Qnil, mesg);
  }
  
  void
  rb_loaderror_with_path(VALUE path, const char *fmt, ...)
  {
      va_list args;
      VALUE mesg;
  
      va_start(args, fmt);
      mesg = rb_enc_vsprintf(rb_locale_encoding(), fmt, args);
      va_end(args);
      raise_loaderror(path, mesg);
  }
  
  void
  rb_notimplement(void)
  {
      rb_raise(rb_eNotImpError,
  	     "%s() function is unimplemented on this machine",
  	     rb_id2name(rb_frame_this_func()));
  }
  
  void
  rb_fatal(const char *fmt, ...)
  {
      va_list args;
      VALUE mesg;
  
      va_start(args, fmt);
      mesg = rb_vsprintf(fmt, args);
      va_end(args);
  
      rb_exc_fatal(rb_exc_new3(rb_eFatal, mesg));
  }
  
  static VALUE
  make_errno_exc(const char *mesg)
  {
      int n = errno;
  
      errno = 0;
      if (n == 0) {
  	rb_bug("rb_sys_fail(%s) - errno == 0", mesg ? mesg : "");
      }
      return rb_syserr_new(n, mesg);
  }
  
  static VALUE
  make_errno_exc_str(VALUE mesg)
  {
      int n = errno;
  
      errno = 0;
      if (!mesg) mesg = Qnil;
      if (n == 0) {
  	const char *s = !NIL_P(mesg) ? RSTRING_PTR(mesg) : "";
  	rb_bug("rb_sys_fail_str(%s) - errno == 0", s);
      }
      return rb_syserr_new_str(n, mesg);
  }
  
  VALUE
  rb_syserr_new(int n, const char *mesg)
  {
      VALUE arg;
      arg = mesg ? rb_str_new2(mesg) : Qnil;
      return rb_syserr_new_str(n, arg);
  }
  
  VALUE
  rb_syserr_new_str(int n, VALUE arg)
  {
      return rb_class_new_instance(1, &arg, get_syserr(n));
  }
  
  void
  rb_syserr_fail(int e, const char *mesg)
  {
      rb_exc_raise(rb_syserr_new(e, mesg));
  }
  
  void
  rb_syserr_fail_str(int e, VALUE mesg)
  {
      rb_exc_raise(rb_syserr_new_str(e, mesg));
  }
  
  void
  rb_sys_fail(const char *mesg)
  {
      rb_exc_raise(make_errno_exc(mesg));
  }
  
  void
  rb_sys_fail_str(VALUE mesg)
  {
      rb_exc_raise(make_errno_exc_str(mesg));
  }
  
  #ifdef RUBY_FUNCTION_NAME_STRING
  void
  rb_sys_fail_path_in(const char *func_name, VALUE path)
  {
      int n = errno;
  
      errno = 0;
      rb_syserr_fail_path_in(func_name, n, path);
  }
  
  void
  rb_syserr_fail_path_in(const char *func_name, int n, VALUE path)
  {
      VALUE args[2];
  
      if (!path) path = Qnil;
      if (n == 0) {
  	const char *s = !NIL_P(path) ? RSTRING_PTR(path) : "";
  	if (!func_name) func_name = "(null)";
  	rb_bug("rb_sys_fail_path_in(%s, %s) - errno == 0",
  	       func_name, s);
      }
      args[0] = path;
      args[1] = rb_str_new_cstr(func_name);
      rb_exc_raise(rb_class_new_instance(2, args, get_syserr(n)));
  }
  #endif
  
  void
  rb_mod_sys_fail(VALUE mod, const char *mesg)
  {
      VALUE exc = make_errno_exc(mesg);
      rb_extend_object(exc, mod);
      rb_exc_raise(exc);
  }
  
  void
  rb_mod_sys_fail_str(VALUE mod, VALUE mesg)
  {
      VALUE exc = make_errno_exc_str(mesg);
      rb_extend_object(exc, mod);
      rb_exc_raise(exc);
  }
  
  void
  rb_mod_syserr_fail(VALUE mod, int e, const char *mesg)
  {
      VALUE exc = rb_syserr_new(e, mesg);
      rb_extend_object(exc, mod);
      rb_exc_raise(exc);
  }
  
  void
  rb_mod_syserr_fail_str(VALUE mod, int e, VALUE mesg)
  {
      VALUE exc = rb_syserr_new_str(e, mesg);
      rb_extend_object(exc, mod);
      rb_exc_raise(exc);
  }
  
  void
  rb_sys_warning(const char *fmt, ...)
  {
      char buf[BUFSIZ];
      va_list args;
      int errno_save;
  
      errno_save = errno;
  
      if (!RTEST(ruby_verbose)) return;
  
      snprintf(buf, BUFSIZ, "warning: %s", fmt);
      snprintf(buf+strlen(buf), BUFSIZ-strlen(buf), ": %s", strerror(errno_save));
  
      va_start(args, fmt);
      warn_print(buf, args);
      va_end(args);
      errno = errno_save;
  }
  
  void
  rb_load_fail(VALUE path, const char *err)
  {
      VALUE mesg = rb_str_buf_new_cstr(err);
      rb_str_cat2(mesg, " -- ");
      rb_str_append(mesg, path);	/* should be ASCII compatible */
      raise_loaderror(path, mesg);
  }
  
  void
  rb_error_frozen(const char *what)
  {
      rb_raise(rb_eRuntimeError, "can't modify frozen %s", what);
  }
  
  #undef rb_check_frozen
  void
  rb_check_frozen(VALUE obj)
  {
      rb_check_frozen_internal(obj);
  }
  
  void
  rb_error_untrusted(VALUE obj)
  {
  }
  
  #undef rb_check_trusted
  void
  rb_check_trusted(VALUE obj)
  {
  }
  
  void
  rb_check_copyable(VALUE obj, VALUE orig)
  {
      if (!FL_ABLE(obj)) return;
      rb_check_frozen_internal(obj);
      if (!FL_ABLE(orig)) return;
      if ((~RBASIC(obj)->flags & RBASIC(orig)->flags) & FL_TAINT) {
  	if (rb_safe_level() > 0) {
  	    rb_raise(rb_eSecurityError, "Insecure: can't modify %"PRIsVALUE,
  		     RBASIC(obj)->klass);
  	}
      }
  }
  
  void
  Init_syserr(void)
  {
      rb_eNOERROR = set_syserr(0, "NOERROR");
  #define defined_error(name, num) set_syserr((num), (name));
  #define undefined_error(name) set_syserr(0, (name));
  #include "known_errors.inc"
  #undef defined_error
  #undef undefined_error
  }
  