Difference between $stdout and STDOUT in Ruby

$stdout is a global variable that represents the current standard output. STDOUT is a constant representing standard output and is typically the default value of $stdout. With STDOUT being a constant, you shouldn’t re-define it, however, you can re-define $stdout without errors/warnings (re-defining STDOUT will raise a warning). for example, you can do: Same goes for $stderr and STDERR So, to answer the other part of your question, use the global variables … Read more

write() to stdout and printf output not interleaved?

Printf is buffered. You can force printf to ‘flush’ its buffer using the fflush call: In general, printf() being buffered is a good thing. Unbuffered output, particularly to visible consoles that require screen updates and such, is slow. Slow enough that an application that is printf’ing a lot can be directly slowed down by it (especially on … Read more

How to open every file in a folder

Os You can list all files in the current directory using os.listdir: Glob Or you can list only some files, depending on the file pattern using the glob module: It doesn’t have to be the current directory you can list them in any path you want: Pipe Or you can even use the pipe as you specified using fileinput And … Read more

What does it mean to write to stdout in C?

That means that you are printing output on the main output device for the session… whatever that may be. The user’s console, a tty session, a file or who knows what. What that device may be varies depending on how the program is being run and from where. The following command will write to the … Read more

The difference between stdout and STDOUT_FILENO

stdout is a FILE* “constant” giving the standard outout stream. So obviously fprintf(stdout, “x=%d\n”, x); has the same behavior as printf(“x=%d\n”, x);; you use stdout for <stdio.h> functions like fprintf, fputs etc.. STDOUT_FILENO is an integer file descriptor (actually, the integer 1). You might use it for write syscall. The relation between the two is STDOUT_FILENO == fileno(stdout) (Except after you do weird things like fclose(stdout);, or perhaps some freopen after some fclose(stdin), which you should … Read more

Scanf/Printf double variable C

For variable argument functions like printf and scanf, the arguments are promoted, for example, any smaller integer types are promoted to int, float is promoted to double. scanf takes parameters of pointers, so the promotion rule takes no effect. It must use %f for float* and %lf for double*. printf will never see a float … Read more

Confused about stdin, stdout and stderr?

Standard input – this is the file handle that your process reads to get information from you. Standard output – your process writes conventional output to this file handle. Standard error – your process writes diagnostic output to this file handle. That’s about as dumbed-down as I can make it 🙂 Of course, that’s mostly by convention. There’s nothing stopping … Read more