Class: Process::Status

Inherits:
Object show all
Defined in:
process.c,
process.c

Overview

*******************************************************************

<code>Process::Status</code> encapsulates the information on the
status of a running or terminated system process. The built-in
variable <code>$?</code> is either +nil+ or a
<code>Process::Status</code> object.

   fork { exit 99 }   #=> 26557
   Process.wait       #=> 26557
   $?.class           #=> Process::Status
   $?.to_i            #=> 25344
   $? >> 8            #=> 99
   $?.stopped?        #=> false
   $?.exited?         #=> true
   $?.exitstatus      #=> 99

Posix systems record information on processes using a 16-bit
integer.  The lower bits record the process status (stopped,
exited, signaled) and the upper bits possibly contain additional
information (for example the program's return code in the case of
exited processes). Pre Ruby 1.8, these bits were exposed directly
to the Ruby program. Ruby now encapsulates these in a
<code>Process::Status</code> object. To maximize compatibility,
however, these objects retain a bit-oriented interface. In the
descriptions that follow, when we talk about the integer value of
_stat_, we're referring to this 16 bit value.

Instance Method Summary collapse

Instance Method Details

#&(num) ⇒ Fixnum

Logical AND of the bits in stat with num.

fork { exit 0x37 }
Process.wait
sprintf('%04x', $?.to_i)       #=> "3700"
sprintf('%04x', $? & 0x1e00)   #=> "1600"

Returns:



462
463
464
465
466
467
468
 
# File 'process.c', line 462

static VALUE
pst_bitand(VALUE st1, VALUE st2)
{
    int status = PST2INT(st1) & NUM2INT(st2);

    return INT2NUM(status);
}

#==(other) ⇒ Boolean

Returns true if the integer value of stat equals other.

Returns:

  • (Boolean) 


442
443
444
445
446
447
 
# File 'process.c', line 442

static VALUE
pst_equal(VALUE st1, VALUE st2)
{
    if (st1 == st2) return Qtrue;
    return rb_equal(pst_to_i(st1), st2);
}

#>>(num) ⇒ Fixnum

Shift the bits in stat right num places.

fork { exit 99 }   #=> 26563
Process.wait       #=> 26563
$?.to_i            #=> 25344
$? >> 8            #=> 99

Returns:



483
484
485
486
487
488
489
 
# File 'process.c', line 483

static VALUE
pst_rshift(VALUE st1, VALUE st2)
{
    int status = PST2INT(st1) >> NUM2INT(st2);

    return INT2NUM(status);
}

#coredump? ⇒ Boolean

Returns true if stat generated a coredump when it terminated. Not available on all platforms.

Returns:

  • (Boolean)

Returns:

  • (Boolean) 


650
651
652
653
654
655
656
657
658
659
660
661
662
663
 
# File 'process.c', line 650

static VALUE
pst_wcoredump(VALUE st)
{
#ifdef WCOREDUMP
    int status = PST2INT(st);

    if (WCOREDUMP(status))
	return Qtrue;
    else
	return Qfalse;
#else
    return Qfalse;
#endif
}

#exited? ⇒ Boolean

Returns true if stat exited normally (for example using an exit() call or finishing the program).

Returns:

  • (Boolean)

Returns:

  • (Boolean) 


581
582
583
584
585
586
587
588
589
590
 
# File 'process.c', line 581

static VALUE
pst_wifexited(VALUE st)
{
    int status = PST2INT(st);

    if (WIFEXITED(status))
	return Qtrue;
    else
	return Qfalse;
}

#exitstatus ⇒ Fixnum?

Returns the least significant eight bits of the return code of stat. Only available if exited? is true.

fork { }           #=> 26572
Process.wait       #=> 26572
$?.exited?         #=> true
$?.exitstatus      #=> 0

fork { exit 99 }   #=> 26573
Process.wait       #=> 26573
$?.exited?         #=> true
$?.exitstatus      #=> 99

Returns:



612
613
614
615
616
617
618
619
620
 
# File 'process.c', line 612

static VALUE
pst_wexitstatus(VALUE st)
{
    int status = PST2INT(st);

    if (WIFEXITED(status))
	return INT2NUM(WEXITSTATUS(status));
    return Qnil;
}

#inspect ⇒ String

Override the inspection method.

system("false")
p $?.inspect #=> "#<Process::Status: pid 12861 exit 1>"

Returns:



413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
 
# File 'process.c', line 413

static VALUE
pst_inspect(VALUE st)
{
    rb_pid_t pid;
    int status;
    VALUE vpid, str;

    vpid = pst_pid(st);
    if (NIL_P(vpid)) {
        return rb_sprintf("#<%s: uninitialized>", rb_class2name(CLASS_OF(st)));
    }
    pid = NUM2PIDT(vpid);
    status = PST2INT(st);

    str = rb_sprintf("#<%s: ", rb_class2name(CLASS_OF(st)));
    pst_message(str, pid, status);
    rb_str_cat2(str, ">");
    return str;
}

#pid ⇒ Fixnum

Returns the process ID that this status object represents.

fork { exit }   #=> 26569
Process.wait    #=> 26569
$?.pid          #=> 26569

Returns:



334
335
336
337
338
 
# File 'process.c', line 334

static VALUE
pst_pid(VALUE st)
{
    return rb_attr_get(st, rb_intern("pid"));
}

#signaled? ⇒ Boolean

Returns true if stat terminated because of an uncaught signal.

Returns:

  • (Boolean)

Returns:

  • (Boolean) 


540
541
542
543
544
545
546
547
548
549
 
# File 'process.c', line 540

static VALUE
pst_wifsignaled(VALUE st)
{
    int status = PST2INT(st);

    if (WIFSIGNALED(status))
	return Qtrue;
    else
	return Qfalse;
}

#stopped? ⇒ Boolean

Returns true if this process is stopped. This is only returned if the corresponding wait call had the WUNTRACED flag set.

Returns:

  • (Boolean)

Returns:

  • (Boolean) 


501
502
503
504
505
506
507
508
509
510
 
# File 'process.c', line 501

static VALUE
pst_wifstopped(VALUE st)
{
    int status = PST2INT(st);

    if (WIFSTOPPED(status))
	return Qtrue;
    else
	return Qfalse;
}

#stopsig ⇒ Fixnum?

Returns the number of the signal that caused stat to stop (or nil if self is not stopped).

Returns:



521
522
523
524
525
526
527
528
529
 
# File 'process.c', line 521

static VALUE
pst_wstopsig(VALUE st)
{
    int status = PST2INT(st);

    if (WIFSTOPPED(status))
	return INT2NUM(WSTOPSIG(status));
    return Qnil;
}

#success? ⇒ true, ...

Returns true if stat is successful, false if not. Returns nil if exited? is not true.

Returns:

  • (true, false, nil)

Returns:

  • (Boolean) 


631
632
633
634
635
636
637
638
639
 
# File 'process.c', line 631

static VALUE
pst_success_p(VALUE st)
{
    int status = PST2INT(st);

    if (!WIFEXITED(status))
	return Qnil;
    return WEXITSTATUS(status) == EXIT_SUCCESS ? Qtrue : Qfalse;
}

#termsig ⇒ Fixnum?

Returns the number of the signal that caused stat to terminate (or nil if self was not terminated by an uncaught signal).

Returns:



561
562
563
564
565
566
567
568
569
 
# File 'process.c', line 561

static VALUE
pst_wtermsig(VALUE st)
{
    int status = PST2INT(st);

    if (WIFSIGNALED(status))
	return INT2NUM(WTERMSIG(status));
    return Qnil;
}

#to_i ⇒ Fixnum #to_int ⇒ Fixnum

Returns the bits in stat as a Fixnum. Poking around in these bits is platform dependent.

fork { exit 0xab }         #=> 26566
Process.wait               #=> 26566
sprintf('%04x', $?.to_i)   #=> "ab00"

Overloads:



315
316
317
318
319
 
# File 'process.c', line 315

static VALUE
pst_to_i(VALUE st)
{
    return rb_iv_get(st, "status");
}

#to_s ⇒ String

Show pid and exit status as a string.

system("false")
p $?.to_s         #=> "pid 12766 exit 1"

Returns:



386
387
388
389
390
391
392
393
394
395
396
397
398
399
 
# File 'process.c', line 386

static VALUE
pst_to_s(VALUE st)
{
    rb_pid_t pid;
    int status;
    VALUE str;

    pid = NUM2PIDT(pst_pid(st));
    status = PST2INT(st);

    str = rb_str_buf_new(0);
    pst_message(str, pid, status);
    return str;
}