_lock_file

發行項
06/09/2015

鎖定 FILE 物件確保並行存取 FILE 物件的執行緒的一致性。

void _lock_file(
   FILE* file
);

參數

file
檔案控制代碼。

備註

_lock_file 函式鎖定 file指定的 FILE 物件。基礎檔案未由 _lock_file鎖定。使用 _unlock_file 釋放在檔案的鎖定。在執行緒必須與呼叫 _lock_file 和 _unlock_file 。

需求

常式	必要的標頭
_lock_file	<stdio.h>

如需更多關於相容性的資訊，請參閱入門介紹中的相容性 (Compatibility) 。

範例

// crt_lock_file.c
// This example creates multiple threads that write to standard output
// concurrently, first with _file_lock, then without.

#include <stdio.h>
#include <process.h>// _beginthread
#include <windows.h>// HANDLE

void Task_locked( void* str )
{
    for( int i=0; i<1000; ++i )
    {
        _lock_file( stdout );
        for( char* cp = (char*)str; *cp; ++cp )
        {
            _fputc_nolock( *cp, stdout );
        }
        _unlock_file( stdout );
    }
}

void Task_unlocked( void* str )
{
    for( int i=0; i<1000; ++i )
    {
        for( char* cp = (char*)str; *cp; ++cp )
        {
            fputc( *cp, stdout );
        }
    }
}

int main()
{
    HANDLE h[3];
    h[0] = (HANDLE)_beginthread( &Task_locked, 0, "First\n" );
    h[1] = (HANDLE)_beginthread( &Task_locked, 0, "Second\n" );
    h[2] = (HANDLE)_beginthread( &Task_locked, 0, "Third\n" );

    WaitForMultipleObjects( 3, h, true, INFINITE );

    h[0] = (HANDLE)_beginthread( &Task_unlocked, 0, "First\n" );
    h[1] = (HANDLE)_beginthread( &Task_unlocked, 0, "Second\n" );
    h[2] = (HANDLE)_beginthread( &Task_unlocked, 0, "Third\n" );

    WaitForMultipleObjects( 3, h, true, INFINITE );
}