CODEWITHSUNDEEP
rstdoutbinary-data
eold
eold

Reputation: 6052

How to write raw type / bytes to stdout?

I am struggling for quite some time with outputting a raw type to standard output. Here is what I tried and did not work the desired way:

r <- as.raw(c(0x41, 0x00, 0x43)) # r = "A\0C"
cat(rawToChar(r)) # displays warning and skips data after NULL (outputs "A")
cat(r) # outputs "41 00 43"
writeBin(r, stdout()) # error: can only write to binary connection

I am looking for a way to get all three bytes / characters printed to stdout.

Upvotes: 6

Views: 2327

Answers (1)

Matt Shotwell
Matt Shotwell

Reputation: 341

If you are using an operating system that has a 'cat' or similar program, we can pipe arbitrary data to stdout like so:

con <- pipe("cat", "wb")
writeBin(as.raw(c(0x41, 0x00, 0x43)), con)
flush(con)

This has been an issue for some time, especially because we would like to use R for common gateway interface (CGI). I don't believe there is a more direct route, but you might look at the RApache source code, to see how the sendBin function is implemented.

Upvotes: 8

Related Questions