Preface
Having seen countless times how people always create files using a timestamp + arc4random(), I felt deeply frustrated. Doesn’t the operating system provide a relevant function? So I found the following code to solve the problem of filename conflicts when creating files.
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/* Create a recording file */
NSString *filePath = [@"~/Movies/AVScreenShackRecording_XXXXXX" stringByStandardizingPath];
char *screenRecordingFileName = strdup([filePath fileSystemRepresentation]);
if (screenRecordingFileName)
{
int fileDescriptor = mkstemp(screenRecordingFileName);
if (fileDescriptor != -1)
{
NSString *filenameStr = [[NSFileManager defaultManager] stringWithFileSystemRepresentation:screenRecordingFileName length:strlen(screenRecordingFileName)];
NSLog(@"唯一的文件名:%@",filenameStr);
}
remove(screenRecordingFileName);
free(screenRecordingFileName);
}
Before use 
During the process 
After completion 
Remember that the file suffix needs to include XXXXXX — each X represents one character of digits + letters Note: It’s best to use 6 X’s or more. See Linux reference
The key is to understand the following two functions:
strdup() is a commonly used string copy function in C
mkstemp() creates and opens a file with a unique filename in the system
OK, hope this helps
End of article