When is memory actually freed in Objective-C? -

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i'm trying understand memory management stuff in objective-c. if see memory usage listed activity monitor, looks memory not being freed (i mean column rsize). in "object allocations" looks fine. here simple code:

#import <foundation/foundation.h>  int main (int argc, const char * argv[]) { nsautoreleasepool * pool = [[nsautoreleasepool alloc] init];   nsinteger i, k=10000; while (k>0) {     nsmutablearray *array = [[nsmutablearray alloc]init];      (i=0;i<1000*k; i++) {         nsstring *srtring = [[nsstring alloc] initwithstring:@"string...."];         [array addobject:srtring];         [srtring release];         srtring = nil;     }      [array release];     array = nil;     k-=500;  }  [nsthread sleepfortimeinterval:5]; [pool release];  return 0; }

as retain , release it's cool, balanced. rsize decreases after quitting little program. possible "clean" memory somehow before quitting?

no point in trying scrub memory before quitting; you're quitting, sparse resources own returned system.

a common misconception free() (the underlying mechanic release) returns memory system immediately; doesn't in implementations, rather adds internal free list; on memory kept around application use, liberated system if asked for. second time loop rolls around, application reuses free memory allocate rather requesting more system, making smoother everybody.


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