A bson_t may contain its data directly or may contain pointers to heap−allocated memory. Overwriting an existing bson_t or allowing a stack−allocated bson_t to go out of scope may cause a memory leak. A bson_t should always be destroyed with bson_destroy().
A bson_t pointer used as an out parameter must point to valid overwritable storage for a new bson_t which must be one of:
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1. |
Uninitialized storage for a bson_t. | ||
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2. |
A zero−initialized bson_t object. | ||
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3. |
A bson_t object initialized with BSON_INITIALIZER. | ||
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4. |
A bson_t object not created with bson_new() that was destroyed with bson_destroy(). |
This can be on the stack:
bson_t
stack_doc = BSON_INITIALIZER;
example_get_doc (&stack_doc);
bson_destroy (&stack_doc);
Or on the heap:
bson_t
*heap_doc = bson_malloc (sizeof (bson_t));
example_get_doc (heap_doc);
bson_destroy (heap_doc);
bson_free (heap_doc);
Omitting bson_destroy() in either case may cause memory leaks.
WARNING:
Passing a bson_t pointer obtained from bson_new() as an out parameter will result in a leak of the bson_t struct.
bson_t
*heap_doc = bson_new ();
example_get_doc (heap_doc);
bson_destroy (heap_doc); // Leaks the `bson_t` struct!
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