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read file   statement

read file [#]deviceID, address, numBytes

This statement reads numBytes bytes from the open file or serial port specified by deviceID (starting at the current "file mark" position), and copies them into memory starting at the address specified by address. This is the fastest way to read large amounts of data from a file; it's also well suited for reading data whose format you may not know in advance.

This program fragment quickly loads an array with the data read from a file. It's assumed that the binary image of the array was previously saved to the file using a statement like write file (see the example accompanying the write file statement).

_maxSubscript = 200
dim myArray(_maxSubscript)
arrayBytes = (_maxSubscript+1) * sizeof(int)
read file #1, @myArray(0), arrayBytes

If read file attempts to read past the end of the file (because numBytes> was too large), FutureBasic generates an error.

See also
open; read#; write file