Book Image

Go Systems Programming

Book Image

Go Systems Programming

Overview of this book

Go is the new systems programming language for Linux and Unix systems. It is also the language in which some of the most prominent cloud-level systems have been written, such as Docker. Where C programmers used to rule, Go programmers are in demand to write highly optimized systems programming code. Created by some of the original designers of C and Unix, Go expands the systems programmers toolkit and adds a mature, clear programming language. Traditional system applications become easier to write since pointers are not relevant and garbage collection has taken away the most problematic area for low-level systems code: memory management. This book opens up the world of high-performance Unix system applications to the beginning Go programmer. It does not get stuck on single systems or even system types, but tries to expand the original teachings from Unix system level programming to all types of servers, the cloud, and the web.
Table of Contents (13 chapters)

Sparse files in Go

Large files that are created with the os.Seek() function may have holes in them and occupy fewer disk blocks than files with the same size, but without holes in them; such files are called sparse files. This section will develop a program that creates sparse files.

The Go code of sparse.go will be presented in three parts. The first part is the following:

package main 
 
import ( 
   "fmt" 
   "log" 
   "os" 
   "path/filepath" 
   "strconv" 
) 

The second part of sparse.go has the following Go code:

func main() { 
   if len(os.Args) != 3 { 
         fmt.Printf("usage: %s SIZE filename\n", filepath.Base(os.Args[0])) 
         os.Exit(1) 
   } 
 
   SIZE, _ := strconv.ParseInt(os.Args[1], 10, 64) 
   filename := os.Args[2] 
 
   _, err := os.Stat(filename) 
   if err == nil { 
         fmt.Printf(&quot...