更改线程优先级ERROR_INVALID_HANDLE

Question

我试图在脚本中更改线程优先级，但没有成功，这里是详细信息。

$thr = threads->new(\&someFunction, 
        $shared variable 1, 
        $shared variable 2, 
        ); 

我试过使用threads::State;

$thr->priority(2); 

没有成功

所以，我认为Win32::API必须努力

my $functionGetLastError= Win32::API->new('Kernel32', 
              'GetLastError', 
              '', 
              'N' 
             ); 
my $functionSetThreadPriority= Win32::API->new('Kernel32', 
               'SetThreadPriority', 
               'II', # I've tried 'PI' and 'II' as well 
               'N' 
              ); 
my $h = $thr->_handle(); 
my $success = $functionSetThreadPriority->Call($h, 2); 
warn "Return Error #".$functionGetLastError->Call() if !$success; 

再次，没有成功：（，但现在我有一个线索，该脚本返回错误号

最后错误6

从MSDN site, System Error Codes (0-499)，似乎错误是

ERROR_INVALID_HANDLE

我在做什么错？

Answer 1

$thread->_handle奇怪地返回HANDLE*，而SetThreadPriority预计HANDLE。您需要取消引用指针，你可以做如下：

use constant THREAD_PRIORITY_HIGHEST => 2; 

sub SetThreadPriority { 
    my ($thread, $priority) = @_; 

    # $thread->_handle() returns a HANDLE*. 
    my $handle_ptr = $thread->_handle(); 
    my $packed_handle = unpack('P'.HANDLE_SIZE, pack(PTR_FORMAT, $handle_ptr)); 
    my $handle  = unpack(HANDLE_FORMAT, $packed_handle); 

    state $SetThreadPriority = (
     Win32::API->new('Kernel32', 'SetThreadPriority', 'Ni', 'i') 
     or die("Loading SetThreadPriority: $^E\n") 
    ); 

    return $SetThreadPriority->Call($handle, $priority); 
} 

---

下面是完整的测试程序：

，您可以使用 $^E

use strict; 
use warnings; 
use feature qw(say state); 

use threads; 
use threads::shared; 

use Carp  qw(croak); 
use Config  qw(%Config); 
use Win32::API qw(); 

sub uint_format { 
    $_[0] == 4 ? 'L' 
    : $_[0] == 8 ? 'Q' 
    : croak("Unsupported") 
} 

use constant PTR_SIZE => $Config{ptrsize}; 
use constant PTR_FORMAT => uint_format(PTR_SIZE); 

use constant HANDLE_SIZE => PTR_SIZE; 
use constant HANDLE_FORMAT => PTR_FORMAT; 

use constant THREAD_PRIORITY_HIGHEST => 2; 

sub SetThreadPriority { 
    my ($thread, $priority) = @_; 

    # $thread->_handle() returns a HANDLE*. 
    my $handle_ptr = $thread->_handle(); 
    my $packed_handle = unpack('P'.HANDLE_SIZE, pack(PTR_FORMAT, $handle_ptr)); 
    my $handle  = unpack(HANDLE_FORMAT, $packed_handle); 

    state $SetThreadPriority = (
     Win32::API->new('Kernel32', 'SetThreadPriority', 'Ni', 'i') 
     or die("Loading SetThreadPriority: $^E\n") 
    ); 

    return $SetThreadPriority->Call($handle, $priority); 
} 

{ 
    my $done :shared = 0; 

    my $thread = async { 
     { lock($done); cond_wait($done) while !$done; } 
    }; 

    my $rv = SetThreadPriority($thread, THREAD_PRIORITY_HIGHEST); 
    say $rv ? "Success" : "Error: $^E"; 

    { lock($done); $done = 1; cond_broadcast($done); } 
    $thread->join(); 
} 

---

公告访问GetLastError。

SetThreadPriority($handle, THREAD_PRIORITY_HIGHEST) 
    or die("SetThreadPriority: $^E\n"; 

Answer 2

ERROR_INVALID_HANDLE

这表明什么_handle返回是不是的Win32 API ::理解。我怀疑“P”想要一个字符串缓冲区而不是一个整数转换的指针。 “我”可能是错误的东西，因为它在64位上的大小是错误的，我会自己尝试“N”。

此外，对于将来在Unix上遇到此问题的读者：请尝试我的POSIX::RT::Scheduler模块。