llgo/c/fcntl:demo

_demo/fcntl/fcntl.go

@@ -0,0 +1,77 @@
+package main
+
+import (
+	"github.com/goplus/llgo/c"
+	"github.com/goplus/llgo/c/fcntl"
+	"github.com/goplus/llgo/c/os"
+	"unsafe"
+)
+
+func main() {
+
+	filename := c.Str("testfile.txt")
+	data := c.Str("Hello, fcntl!")
+
+	var buffer [20]c.Char
+
+	// Open a file, O_CREAT|O_WRONLY|O_TRUNC means create, write only, or clear the file
+	fd := fcntl.Open(filename, fcntl.O_CREAT|fcntl.O_WRONLY|fcntl.O_TRUNC, 0644)
+	if fd == -1 {
+		c.Printf(c.Str("open error\n"))
+		return
+	}
+
+	// Writing data to a file
+	bytesWritten := os.Write(fd, c.Pointer(data), c.Strlen(data))
+	if bytesWritten == -1 {
+		c.Printf(c.Str("write error\n"))
+		os.Close(fd)
+		return
+	}
+	c.Printf(c.Str("Written %ld bytes to %s\n"), bytesWritten, filename)
+
+	// Get file status flags
+	flags := fcntl.FcNtl(fd, fcntl.F_GETFL)
+	if flags == -1 {
+		c.Printf(c.Str("fcntl error\n"))
+		os.Close(fd)
+		return
+	}
+	c.Printf(c.Str("File flags: %d\n"), flags)
+
+	// Set the file status flag to non-blocking mode
+	if fcntl.FcNtl(fd, fcntl.F_SETFL, flags|fcntl.O_NONBLOCK) == -1 {
+		c.Printf(c.Str("fcntl error\n"))
+		os.Close(fd)
+		return
+	}
+	c.Printf(c.Str("set file status successfully\n"))
+
+	c.Printf(c.Str("111"))
+	// Close file
+	os.Close(fd)
+
+	// Reopen the file, O_RDONLY means read-only
+	fd = fcntl.Open(filename, fcntl.O_RDONLY)
+	if fd == -1 {
+		c.Printf(c.Str("open error\n"))
+		return
+	}
+
+	// Reading data from a file
+	// &buffer[:][0]
+	// unsafe.SliceData(buffer[:])
+	bytesRead := os.Read(fd, c.Pointer(unsafe.SliceData(buffer[:])), unsafe.Sizeof(buffer)-1)
+	if bytesRead == -1 {
+		c.Printf(c.Str("read error\n"))
+		os.Close(fd)
+		return
+	}
+
+	// Ensure that the buffer is null-terminated
+	buffer[bytesRead] = c.Char(0)
+	c.Printf(c.Str("Read %ld bytes: %s\n"), bytesRead, buffer)
+
+	// Close file
+	os.Close(fd)
+}