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The '''_MEMEXISTS''' function returns true (-1) if the memory block variable name specified exists in memory and false (0) if it does not.


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:::  ret = '''[[_MEMEXISTS]] ('''''memblock''''')'''


''Details:''
* The memblock variable name should have been created using [[DIM]] blockname [[AS]] [[_MEM]] type ([[DIM]].
* The function verifies that the memory variable exists in memory before using a passed block to avoid generating QB64 errors.
* Typically, this function is used by a [[DECLARE LIBRARY|LIBRARY]] [[SUB]] or [[FUNCTION]] which accepts a [[_MEM]] structure as input to avoid an error.


''See Also:''
* [[_MEM (function)]]
* [[_MEMELEMENT]], [[_MEMCOPY]]
* [[_MEMIMAGE]], [[_MEMNEW]]
* [[_MEMGET]], [[_MEMPUT]]
* [[_MEMFILL]], [[_MEMFREE]]


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