Question

Python’s os.path.getctime on the Mac (and under Unix in general) does not give the date when a file was created but “the time of the last change” (according to the docs at least). On the other hand in the Finder I can see the real file creation time so this information is kept by HFS+.

Do you have any suggestions on how to obtain the file creation time on the Mac in a Python program?

Answer 1

Use the st_birthtime property on the result of a call to os.stat() (or fstat/lstat).

def get_creation_time(path):
    return os.stat(path).st_birthtime

You can convert the integer result to a datetime object using datetime.datetime.fromtimestamp().

_{For some reason I don’t think this worked on Mac OS X when this answer was first written, but I could be mistaken, and it does work now, even with older versions of Python. The old answer is below for posterity.}

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Using ctypes to access the system call stat64 (works with Python 2.5+):

from ctypes import *

class struct_timespec(Structure):
    _fields_ = [('tv_sec', c_long), ('tv_nsec', c_long)]

class struct_stat64(Structure):
    _fields_ = [
        ('st_dev', c_int32),
        ('st_mode', c_uint16),
        ('st_nlink', c_uint16),
        ('st_ino', c_uint64),
        ('st_uid', c_uint32),
        ('st_gid', c_uint32), 
        ('st_rdev', c_int32),
        ('st_atimespec', struct_timespec),
        ('st_mtimespec', struct_timespec),
        ('st_ctimespec', struct_timespec),
        ('st_birthtimespec', struct_timespec),
        ('dont_care', c_uint64 * 8)
    ]

libc = CDLL('libc.dylib') # or /usr/lib/libc.dylib
stat64 = libc.stat64
stat64.argtypes = [c_char_p, POINTER(struct_stat64)]

def get_creation_time(path):
    buf = struct_stat64()
    rv = stat64(path, pointer(buf))
    if rv != 0:
        raise OSError("Couldn't stat file %r" % path)
    return buf.st_birthtimespec.tv_sec

Using subprocess to call the stat utility:

import subprocess

def get_creation_time(path):
    p = subprocess.Popen(['stat', '-f%B', path],
        stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    if p.wait():
        raise OSError(p.stderr.read().rstrip())
    else:
        return int(p.stdout.read())