48 lines
1.9 KiB
MQL5
48 lines
1.9 KiB
MQL5
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//+------------------------------------------------------------------+
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//| FileHandle.mq5 |
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//| Copyright 2021, MetaQuotes Ltd. |
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//| https://www.mql5.com |
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//+------------------------------------------------------------------+
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#define FILE_DEBUG_PRINT
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#include "..\..\Include\MqlError.mqh"
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#include "..\..\Include\FileHandle.mqh"
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#include "..\..\Include\PRTF.mqh"
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// NB: we will open the same file twice in this script
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// just for demonstration purpose;
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// normally you need only one handle for a file per program instance
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const string dummy = "MQL5Book/dummy";
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//+------------------------------------------------------------------+
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//| Script program start function |
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//+------------------------------------------------------------------+
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void OnStart()
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{
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// create new file or open existing one and empty it
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FileHandle fh1(PRTF(FileOpen(dummy, FILE_TXT | FILE_WRITE | FILE_SHARE_WRITE | FILE_SHARE_READ))); // 1
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// another possible use case
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int h = PRTF(FileOpen(dummy, FILE_TXT | FILE_WRITE | FILE_SHARE_WRITE | FILE_SHARE_READ)); // 2
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FileHandle fh2 = h;
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// one more supported syntax:
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// int f;
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// FileHandle ff(f, FileOpen(dummy, FILE_TXT|FILE_WRITE|FILE_SHARE_WRITE|FILE_SHARE_READ));
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// some data writing could be here
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// ...
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FileClose(~fh1); // explicit close will be detected and gracefully skipped in FileHandle
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// Note: handle h, stored in fh2 is not closed
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// and will be closed automatically in destructor
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/*
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output:
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FileHandle::~FileHandle: Automatic close for handle: 2
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FileHandle::~FileHandle: handle 1 is incorrect, INVALID_FILEHANDLE(5007)
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*/
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}
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//+------------------------------------------------------------------+
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