[iOS][objective-c] when freopen is called, can't pass the next line of code

[ysbaekFox]

Hello all.

I have a problem in qt-iOS environment.

First, my environnment is below.

• XCode Version 12.5
• QT 5.14.2
• Fixed : https://codereview.qt-project.org/c/qt/qtbase/+/314522/1/mkspecs/features/toolchain.prf
• I didn't use QT, I used [projectName].xcodeproj generated as a result of QT Build
• iOS Device 14.6

I want to save the log output from my app as a file on the device.
I've found a very simple way to use it in an iOS environment.

The way I found is to redirect the Console Log and save it to a file.

• https://stackoverflow.com/questions/3184235/how-to-redirect-the-nslog-output-to-file-instead-of-console

When I used this solution, I've actually seen it work and create a Log File.
However, this solution works and doesn't work for some unknown reason. (intermittently does not work)

Is this a bug in QT? Or is there a problem using my solution?

@implementation QIOSApplicationDelegate (QTAppDelegate)
- (BOOL)application:(UIApplication *)application
  didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    NSLog(@"[AppDelegate_Log] didFinishLaunchingWithOptions");
    NSDateFormatter *currrentSystemTime = [[NSDateFormatter alloc] init];
    [currrentSystemTime setDateFormat:@"ddhhmm"];
    NSString *logFileName = @"logcat_";
    NSString *logStartTime = [currrentSystemTime stringFromDate:[NSDate date]];
    logFileName = [logFileName stringByAppendingString:logStartTime];
    logFileName = [logFileName stringByAppendingString:@".log"];
    NSLog(@"[AppDelegate_Log] logFile Name : %@", logFileName);
    
#if TARGET_IPHONE_SIMULATOR == 0
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *logPath = [documentsDirectory stringByAppendingPathComponent:logFileName];
    NSLog(@"[AppDelegate_Log] logFile Path : %@", logPath);

    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSArray *fileList = [fileManager contentsOfDirectoryAtPath:documentsDirectory error:NULL];
    NSLog(@"[AppDelegate_Log] fileList!!!! : %@", fileList);

    freopen([logPath cStringUsingEncoding:NSASCIIStringEncoding],"a+",stderr);
#endif

    NSLog(@"[AppDelegate_Log] Exit");
    return YES;
}
@end