readbytes
readbytes(stream, nb=typemax(Int); all=true)
Read at most nb bytes from the stream, returning a Vector{UInt8} of the bytes read.
If all is true (the default), this function will block repeatedly trying to read all requested bytes, until an error or end-of-file occurs. If all is false, at most one read call is performed, and the amount of data returned is device-dependent. Note that not all stream types support the all option.
Examples
-
Read a fixed number of bytes from a file:
julia> file = open("data.txt", "r"); julia> bytes = readbytes(file, 10) 10-element Array{UInt8,1}: 0x48 0x65 0x6c 0x6c 0x6f 0x20 0x57 0x6f 0x72 0x6cThis example reads 10 bytes from the file "data.txt" and stores them in the
bytesarray. -
Read all available bytes from a network stream:
julia> using Sockets julia> sock = connect("example.com", 80) julia> response = readbytes(sock) 1461-element Array{UInt8,1}: 0x48 0x54 0x54 0x50 0x2f 0x31 0x2e 0x31 0x20 0x32 0x30 0x30 0x20 0x4f 0x4b 0x0d 0x0a ⋮In this example,
readbytesis used to read all available bytes from a network socket. - Specify the maximum number of bytes to read:
julia> file = open("data.txt", "r"); julia> bytes = readbytes(file, 5; all=false) 5-element Array{UInt8,1}: 0x48 0x65 0x6c 0x6c 0x6fBy setting
all=false, only a singlereadcall is made, and the function returns at mostnbbytes.
Common mistake example:
julia> file = open("data.txt", "r");
julia> bytes = readbytes(file, -10)
ERROR: ArgumentError: number of bytes must be non-negativeIn this example, a negative value is passed as the number of bytes to read. The number of bytes must be non-negative. Ensure that the nb argument is always a valid number of bytes to read.
See Also
deserialize, eachline, eof, fd, flush, IOBuffer, ismarked, isopen, isreadonly, mark, nb_available, open, pipeline, position, read, read!, readavailable, readbytes, readbytes!, readline, redirect_stderr, redirect_stdin, reset, seek, seekend, seekstart, serialize, skip, skipchars, TextDisplay, unmark, write, writemime,User Contributed Notes
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