[Overview][Constants][Types][Classes][Procedures and functions][Variables] |
Read data from an untyped file into memory
Source position: line 0
procedure BlockRead( |
var f: ; |
var Buf; |
count: Int64; |
var Result: Int64 |
); |
var f: ; |
var Buf; |
count: LongInt; |
var Result: LongInt |
); |
var f: ; |
var Buf; |
count: Cardinal; |
var Result: Cardinal |
); |
var f: ; |
var Buf; |
count: Word; |
var Result: Word |
); |
var f: ; |
var Buf; |
count: Word; |
var Result: Integer |
); |
var f: ; |
var Buf; |
count: Int64 |
); |
Blockreadreads countor less records from file F. A record is a block of bytes with size specified by the Rewriteor Resetstatement. The result is placed in Buffer, which must contain enough room for Countrecords. The function cannot read partial records. If Resultis specified, it contains the number of records actually read. If Resultisn't specified, and less than Countrecords were read, a run-time error is generated. This behavior can be controlled by the \var{\{\$i\}} switch.
Depending on the state of the \var{\{\$I\}} switch, a runtime error can be generated if there is an error. In the \var{\{\$I-\}} state, use IOResultto check for errors.
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Write data from memory to an untyped file |
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Close a file |
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Open file for reading |
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Assign a name to a file |
Program Example6; { Program to demonstrate the BlockRead and BlockWrite functions. } Var Fin, fout : File; NumRead,NumWritten : Word; Buf : Array[1..2048] of byte; Total : Longint; begin Assign (Fin, Paramstr(1)); Assign (Fout,Paramstr(2)); Reset (Fin,1); Rewrite (Fout,1); Total:=0; Repeat BlockRead (Fin,buf,Sizeof(buf),NumRead); BlockWrite (Fout,Buf,NumRead,NumWritten); inc(Total,NumWritten); Until (NumRead=0) or (NumWritten<>NumRead); Write ('Copied ',Total,' bytes from file ',paramstr(1)); Writeln (' to file ',paramstr(2)); close(fin); close(fout); end.