請教 windows 進(jìn)程打開句柄個數(shù)的限制的問題

bruce_wang_jane

   上周用c的fopen 函數(shù)同時打開很多文件，當(dāng)打開到第47個后，就提示錯誤了， 后續(xù)得文件無法打開了。
剛用perl的open函數(shù)測試，發(fā)現(xiàn)打開到2045的時候才提示“Too many open files”。
請教為何2者差這么多。如何調(diào)高47這個門限值？

http80

Perl flock()函數(shù)
語法
flock FILEHANDLE, OPERATION


定義和使用
支持文件鎖定在指定的文件句柄，使用系統(tǒng)的flock()，fcntl()文件鎖定，或使用lockf()。確切的實(shí)現(xiàn)是依賴于你的系統(tǒng)支持。操作是此處定義的靜態(tài)值之一...

Operation        Result LOCK_SH         Set shared lock.
LOCK_EX         Set exclusive lock.
LOCK_UN         Unlock specified file.
LONG_NB         Set lock without blocking.
返回值
0 設(shè)置/取消鎖定失敗時

1 設(shè)置/取消鎖定成功時

實(shí)例
以下是用法...

這里有一個郵箱附加器 BSD系統(tǒng)：

use Fcntl ':flock'; # import LOCK_* constants

    sub lock {
        flock(MBOX,LOCK_EX);
        # and, in case someone appended
        # while we were waiting...
        seek(MBOX, 0, 2);
    }
    sub unlock {
        flock(MBOX,LOCK_UN);
    }
    open(MBOX, ">>/usr/spool/mail/$ENV{'USER'}")
            or die "Can't open mailbox: $!";
    lock();
    # by www.yiibai.com

    print MBOX $msg,"\n\n";
    unlock();

laputa73

我也想知道啊
之前用erlang的echo server,也是到1000多就掛住了（*2就是2000左右）
有人說要改注冊表，但是沒有搜到怎么改。
感覺是類似的問題
在linux下可以用ulimit改
windows下是什么樣的機(jī)制?

xiyoulaoyuanjia

linux 看看ulimit 能不能修改~~   

laputa73

找到一個說法，說是c api的限制。不過很不甘心啊。
明明有人說可以改的(可氣的是沒有說怎么改)。
MSDN里的描述如下：

C run-time I/O now supports many more open files on Win32 platforms than in previous versions. Up to 2,048 files can be open simultaneously at the lowio level (that is, opened and accessed by means of the _open, _read, _write, and so forth family of I/O functions). Up to 512 files can be open simultaneously at the stdio level (that is, opened and accessed by means of the fopen, fgetc, fputc, and so forth family of functions). The limit of 512 open files at the stdio level can be increased to a maximum of 2,048 by means of the _setmaxstdio function.


Because stdio-level functions, such as fopen, are built on top of the lowio functions, the maximum of 2,048 is a hard upper limit for the number of simultaneously open files accessed through the C run-time library.