fopen() always return NULL on iOS device

Question

File exists in iOS bundle directory. fopen() always return NULL on iOS device, but OK on iOS sumulator, codes as below:

NSString *path = [NSBundle.mainBundle pathForResource:@"yuv420p_640x360" ofType:@"yuv"];
BOOL exists = [NSFileManager.defaultManager fileExistsAtPath:path];
NSLog(@"%d", exists); //prints "1"
const char *path2 = [path UTF8String];
FILE *fp = fopen(path2, "rb+"); //fp is NULL

Environment: macOS 12.0.1, M1 MacBook Pro, iPadOS 15.0

The iOS execution environment is sandboxed, and you can not open a file in the bundle with "writing" mode, since the files in the bundle can not be modified (try with just "r" for the mode). — Christos Koninis, Dec 13 '21 at 09:31
@ChristosKoninis Yeah, finally I just change "rb+" to "rb" and run OK. thanks — Smeegol, Dec 13 '21 at 10:40
Since it helped I am moving my comment to an full answer for better visibility in case some one has the same problem to easily find the solution — Christos Koninis, Dec 13 '21 at 10:51

score 1 · Accepted Answer · answered Dec 13 '21 at 10:51

1

The iOS execution environment is sandboxed, and you can not open a file in the bundle with "writing" mode, since the files in the bundle can not be modified (try with just "r" for the mode).

answered Dec 13 '21 at 10:51

Christos Koninis

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@Smeegol If you find my solution useful please accept it so that others can be helped if they face the same problem – Christos Koninis Dec 13 '21 at 22:09

score 1 · Answer 2 · answered Dec 13 '21 at 11:38

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You cannot open any file in iOS. Apps are sandboxed in iOS i.e. An app can access only its directory and cannot access(read/write) any file outside its directory.

answered Dec 13 '21 at 11:38

Saurav_Sharma

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fopen() always return NULL on iOS device

2 Answers2