How to Combine FFI::new and FFI::free for Optimal Memory Management: Practical Tips

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<p><?php<br>
/**</p>
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<p>Title: How to Combine FFI::new and FFI::free for Optimal Memory Management: Practical Tips</p>
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<p>In modern PHP development, FFI (Foreign Function Interface) provides the ability to directly call C libraries and manage native memory.</p>
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<p>However, careless use of memory allocated with FFI::new can lead to memory leaks or performance issues.</p>
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<p>This article explains in detail how to combine FFI::new and FFI::free for best practices in memory management.<br>
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<p>/**</p>
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<p>Understanding FFI::new and FFI::free</p>
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<p>FFI::new($cType, bool $owned = true): Allocates a block of C-style memory in PHP.</p>
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/**

• 2. Usage Example
  */
  $ffi = FFI::cdef("
  typedef struct {
  int x;
  int y;
  } Point;
  ");

// Automatic memory management
$point1 = $ffi->new("Point"); // $owned defaults to true
$point1->x = 10;
$point1->y = 20;
echo "Automatic memory management: Point1 = ({$point1->x}, {$point1->y})\n";

// Manual memory management
$point2 = $ffi->new("Point", false); // $owned = false
$point2->x = 30;
$point2->y = 40;
echo "Manual memory management: Point2 = ({$point2->x}, {$point2->y})\n";

// Free manually allocated memory
FFI::free($point2);

/**

• 3. Best Practices Summary

• • Avoid frequently allocating large memory blocks with $owned = true inside loops.

• • For short-lived objects, automatic management simplifies code.

• • For large or long-lived objects, manually manage memory and call FFI::free at the appropriate time.

• • Use try/finally or similar mechanisms to ensure manually allocated memory is released even in exceptions.

• Example: Safe release
  */
  $point3 = $ffi->new("Point", false);
  try {
  $point3->x = 50;
  $point3->y = 60;
  echo "Safe memory management: Point3 = ({$point3->x}, {$point3->y})\n";
  } finally {
  FFI::free($point3);
  }

/**

• 4. Practical Tips

• • Encapsulate FFI memory allocation in a management class and automatically release it in the destructor.

• • Avoid mixing references of $owned = true and $owned = false objects to reduce logical errors.

• • For performance-sensitive applications, allocate memory blocks in batches and manage them via pointer operations for efficiency.
    */

echo "PHP FFI memory management example ends\n";