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When I set the option parameter to OSLogEnumeratorReverse, the iteration order of OSLogEnumerator is still from front to back in time
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When I set the options parameter to 0 and the position parameter to the first 5 seconds of the current time, OSLogEnumerator can still iterate over the previous 5 seconds
#import "ViewController.h"
#import <OSLog/OSLog.h>
@interface ViewController ()
@property(strong, nonatomic)OSLogStore *logStore;
@property(strong, nonatomic)NSDateFormatter *formatter;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
NSError *err = nil;
self.logStore = [OSLogStore storeWithScope:OSLogStoreCurrentProcessIdentifier error:&err];
if (!self.logStore || err) {
NSLog(@"error: %@", err);
NSAssert(0, @"");
}
self.formatter = [[NSDateFormatter alloc] init];
[self.formatter setDateFormat:@"[yyyy-MM-dd HH:mm:ss:SSS]"];
}
- (IBAction)addLog:(id)sender {
static int i = 0;
NSLog(@"[test] %@ this is a log with index:%d", [self.formatter stringFromDate:[NSDate date]], i++);
}
- (IBAction)printLogWithReverse:(id)sender {
NSError *err = nil;
NSPredicate *preeicate = [NSPredicate predicateWithFormat:@"composedMessage contains %@" argumentArray:@[@"[test]"]];
OSLogEnumerator *enumer = [self.logStore entriesEnumeratorWithOptions:OSLogEnumeratorReverse position:nil predicate:preeicate error:&err];
if (err) {
NSLog(@"enumer error:%@", err);
NSAssert(0, @"");
}
OSLogEntryLog *entry = nil;
while (entry = [enumer nextObject]) {
NSString *message = [entry composedMessage];
printf("log: %s\n", message.UTF8String);
}
}
- (IBAction)printLogWithPosition:(id)sender {
NSError *err = nil;
NSPredicate *preeicate = [NSPredicate predicateWithFormat:@"composedMessage contains %@" argumentArray:@[@"[test]"]];
NSDate *posDate = [NSDate dateWithTimeIntervalSinceNow:-5];
OSLogPosition *pos = [self.logStore positionWithDate:posDate];
OSLogEnumerator *enumer = [self.logStore entriesEnumeratorWithOptions:0 position:pos predicate:preeicate error:&err];
if (err) {
NSLog(@"enumer error:%@", err);
NSAssert(0, @"");
}
const char *now = [self.formatter stringFromDate:[NSDate date]].UTF8String;
const char *posStart = [self.formatter stringFromDate:posDate].UTF8String;
OSLogEntryLog *entry = nil;
while (entry = [enumer nextObject]) {
NSString *message = [entry composedMessage];
printf("log(now:%s, pos:%s): %s\n", now, posStart, message.UTF8String);
}
}
@end
The method of - (IBAction)printLogWithReverse:(id)sender print result not reversed by time.
log: [test] [2025-02-18 17:35:50:175] this is a log with index:0
log: [test] [2025-02-18 17:35:51:040] this is a log with index:1
log: [test] [2025-02-18 17:35:51:174] this is a log with index:2
log: [test] [2025-02-18 17:35:51:323] this is a log with index:3
log: [test] [2025-02-18 17:35:51:473] this is a log with index:4
log: [test] [2025-02-18 17:35:51:640] this is a log with index:5
log: [test] [2025-02-18 17:35:51:773] this is a log with index:6
log: [test] [2025-02-18 17:35:51:923] this is a log with index:7
The method of - (IBAction)printLogWithPosition:(id) print result should not contain the log from 5 seconds ago because I set the start time position in the position argument
[test] [2025-02-18 17:43:58:741] this is a log with index:0
[test] [2025-02-18 17:43:58:940] this is a log with index:1
[test] [2025-02-18 17:43:59:458] this is a log with index:2
[test] [2025-02-18 17:43:59:923] this is a log with index:3
log(now:[2025-02-18 17:44:51:132], pos:[2025-02-18 17:44:46:032]): [test] [2025-02-18 17:43:58:741] this is a log with index:0
log(now:[2025-02-18 17:44:51:132], pos:[2025-02-18 17:44:46:032]): [test] [2025-02-18 17:43:58:940] this is a log with index:1
log(now:[2025-02-18 17:44:51:132], pos:[2025-02-18 17:44:46:032]): [test] [2025-02-18 17:43:59:458] this is a log with index:2
log(now:[2025-02-18 17:44:51:132], pos:[2025-02-18 17:44:46:032]): [test] [2025-02-18 17:43:59:923] this is a log with index:3
These are known issues with the .currentProcessIdentifier
scope implementation. I talk about this in Your Friend the System Log (search for “87622922”). Unfortunately, I’m not aware of any workaround, other than the obvious: Get all the events and filter them yourself.
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—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"