Class: Process::Status
Overview
Status
encapsulates the information on the status of a running or terminated system process. The built-in variable $?
is either nil
or a Status
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 Status
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 Attribute Summary
-
#coredump? ⇒ Boolean
readonly
Returns
true
if stat generated a coredump when it terminated. -
#exited? ⇒ Boolean
readonly
Returns
true
if stat exited normally (for example using anexit()
call or finishing the program). -
#signaled? ⇒ Boolean
readonly
Returns
true
if stat terminated because of an uncaught signal. -
#stopped? ⇒ Boolean
readonly
Returns
true
if this process is stopped. -
#success? ⇒ Boolean
readonly
Returns
true
if stat is successful,false
if not.
Instance Method Summary
-
#&(num) ⇒ Fixnum
Logical AND of the bits in stat with num.
-
#==(other) ⇒ Boolean
Returns
true
if the integer value of stat equals other. -
#>>(num) ⇒ Fixnum
Shift the bits in stat right num places.
-
#exitstatus ⇒ Fixnum?
Returns the least significant eight bits of the return code of stat.
-
#inspect ⇒ String
Override the inspection method.
-
#pid ⇒ Fixnum
Returns the process ID that this status object represents.
-
#stopsig ⇒ Fixnum?
Returns the number of the signal that caused stat to stop (or
nil
if self is not stopped). -
#termsig ⇒ Fixnum?
Returns the number of the signal that caused stat to terminate (or
nil
if self was not terminated by an uncaught signal). -
#to_i ⇒ Fixnum
Returns the bits in stat as a ::Fixnum.
-
#to_s ⇒ String
Show pid and exit status as a string.
Instance Attribute Details
#coredump? ⇒ Boolean
(readonly)
Returns true
if stat generated a coredump when it terminated. Not available on all platforms.
#exited? ⇒ Boolean
(readonly)
Returns true
if stat exited normally (for example using an exit()
call or finishing the program).
#signaled? ⇒ Boolean
(readonly)
Returns true
if stat terminated because of an uncaught signal.
#stopped? ⇒ Boolean
(readonly)
Returns true
if this process is stopped. This is only returned if the corresponding Process.wait call had the WUNTRACED flag set.
#success? ⇒ Boolean
(readonly)
Returns true
if stat is successful, false
if not. Returns nil
if #exited? is not true
.
Instance Method Details
#&(num) ⇒ Fixnum
#==(other) ⇒ Boolean
Returns true
if the integer value of stat equals other.
#>>(num) ⇒ Fixnum
#exitstatus ⇒ Fixnum?
#inspect ⇒ String
Override the inspection method.
system("false")
p $?.inspect #=> "#<Process::Status: pid 12861 exit 1>"
#pid ⇒ Fixnum
#stopsig ⇒ Fixnum?
Returns the number of the signal that caused stat to stop (or nil
if self is not stopped).
#termsig ⇒ Fixnum?
Returns the number of the signal that caused stat to terminate (or nil
if self was not terminated by an uncaught signal).
#to_s ⇒ String
Show pid and exit status as a string.
system("false")
p $?.to_s #=> "pid 12766 exit 1"