`dprintf`: print formatted text directly to a file descriptor

This already existed as dprintf(3). I now feel stupid for having Implemented fd_printf.

The original post is as follows:

I wrote this while debugging some code, and thought it might be useful to others:

#define _GNU_SOURCE     /* vasprintf() */
-#include <stdarg.h>     /* va_start()/va_end() */
-#include <stdio.h>      /* vasprintf() */
-#include <stdlib.h>     /* free() */
-#include <unistd.h>     /* write() */
-
-int
-fd_printf(int fd, const char *format, ...)
-{
-    va_list arg;
-    int len;
-    char *str;
-
-    va_start(arg, format);
-    len = vasprintf(&str, format, arg);
-    va_end(arg);
-
-    write(fd, str, len);
-
-    free(str);
-    return len;
-}

It is a version of printf that prints to a file descriptor—where fprintf prints to a FILE* data structure.

The appeal of this is that FILE* I/O is buffered—which means mixing it with raw file descriptor I/O is going to produce weird results.

- -

dprintf: print formatted text directly to a file descriptor

`dprintf`: print formatted text directly to a file descriptor