# ReadByte ( filehandle/stream )

# Parameters

filehandle/stream = a valid variable set with the OpenFile, ReadFile command, or OpenTCPStream (v1.52+)

# Description

Once you've opened a disk file (or stream) for reading, use this command to read a single byte at a time from the file/stream. Note, a byte is an integer that can take the values 0..255 and occupies 8 bits of storage. Since characters are stored as byte values this function can be used to read a file one character at a time. Reading beyond the end of file does not result in an error, but each value read will be zero.
Advanced notes
The number that is stored by WriteByte is actually the least significant byte of an integer so negative numbers and numbers above 255 will still have a value between 0..255. Unless you understand how 32 bit integers are stored in 2's compliment notation this will seem strange but it is NOT a bug.
Streams can only be used in Blitz Basic v1.52 or greater.

# Example

; Reading and writing a file using ReadByte and WriteByte functions
; Initialise some variables for the example
Byte1% = 10 ; store 10
Byte2% = 100 ; store 100
Byte3% = 255 ; store 255 ( the maximum value that can be stored in a Byte)
Byte4% = 256 ; try to store 256 this will end up as 0 ( i.e. 256 - 256 = 0 )
Byte5% = 257 ; try to store 257 this will end up as 1 ( i.e. 257 - 256 = 1 )
Byte6% = -1 ; try to store -1 this will end up as 255 ( i.e. 256 -1 = 255 )
Byte7% = -2 ; try to store 256 this will end up as 254 ( i.e. 256 - 2 = 254 )
Byte8% = Asc("A") ; Store the ASCII value for the Character "A" ( i.e. 65 )
; Open a file to write to
fileout = WriteFile("mydata.dat ")
; Write the information to the file
WriteByte( fileout, Byte1 )
WriteByte( fileout, Byte2 )
WriteByte( fileout, Byte3 )
WriteByte( fileout, Byte4 )
WriteByte( fileout, Byte5 )
WriteByte( fileout, Byte6 )
WriteByte( fileout, Byte7 )
WriteByte( fileout, Byte8 )
; Close the file
CloseFile( fileout )
; Open the file to Read
filein = ReadFile("mydata.dat")
Read1 = ReadByte( filein )
Read2 = ReadByte( filein )
Read3 = ReadByte( filein )
Read4 = ReadByte( filein )
Read5 = ReadByte( filein )
Read6 = ReadByte( filein )
Read7 = ReadByte( filein )
Read8 = ReadByte( filein )
; Close the file once reading is finished
CloseFile( filein )
Print "Written - Read"
Write Byte1 + " - " : Print Read1
Write Byte2 + " - " : Print Read2
Write Byte3 + " - " : Print Read3
Write Byte4 + " - " : Print Read4
Write Byte5 + " - " : Print Read5
Write Byte6 + " - " : Print Read6
Write Byte7 + " - " : Print Read7
Write Byte8 + " - " : Print Chr$( Read8 )
WaitKey()

Index
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