ITT: Lazy

Python doesn't care about references:


==1780== Memcheck, a memory error detector
==1780== Copyright (C) 2002-2010, and GNU GPL'd, by Julian Seward et al.
==1780== Using Valgrind-3.6.1-Debian and LibVEX; rerun with -h for copyright info
==1780== Command: python test.py
==1780==
==1780== Invalid read of size 4
==1780==    at 0x80A9804: PyObject_Free (in /usr/bin/python2.7)
==1780==    by 0x80784F5: ??? (in /usr/bin/python2.7)
==1780==    by 0x8112064: ??? (in /usr/bin/python2.7)
==1780==    by 0x8112CB8: ??? (in /usr/bin/python2.7)
==1780==  Address 0x44ff010 is 8 bytes inside a block of size 352 free'd
==1780==    at 0x4027C02: free (vg_replace_malloc.c:366)
==1780==    by 0x43080B3: fclose@@GLIBC_2.1 (iofclose.c:88)
==1780==    by 0x62696C2E: ???
==1780==
...
<cut because it was too large for submission>
...
==1780==
==1780== Invalid read of size 4
==1780==    at 0x80A9804: PyObject_Free (in /usr/bin/python2.7)
==1780==    by 0x80784F5: ??? (in /usr/bin/python2.7)
==1780==    by 0x808C8CA: ??? (in /usr/bin/python2.7)
==1780==    by 0x8090C1D: ??? (in /usr/bin/python2.7)
==1780==    by 0x811A2E8: PyInterpreterState_Clear (in /usr/bin/python2.7)
==1780==    by 0x811C132: Py_Finalize (in /usr/bin/python2.7)
==1780==    by 0x812C55A: Py_Main (in /usr/bin/python2.7)
==1780==    by 0x805DA0A: main (in /usr/bin/python2.7)
==1780==  Address 0x4a6f010 is 3,376 bytes inside a block of size 4,370 free'd
==1780==    at 0x4027C02: free (vg_replace_malloc.c:366)
==1780==    by 0x811709F: PyMarshal_ReadLastObjectFromFile (in /usr/bin/python2.7)
==1780==    by 0x810FDCE: ??? (in /usr/bin/python2.7)
==1780==    by 0x62696C2E: ???
==1780== Invalid read of size 4
==1780==    at 0x80A9804: PyObject_Free (in /usr/bin/python2.7)
==1780==    by 0x80606D1: PyGrammar_RemoveAccelerators (in /usr/bin/python2.7)
==1780==    by 0x811C1A0: Py_Finalize (in /usr/bin/python2.7)
==1780==    by 0x812C55A: Py_Main (in /usr/bin/python2.7)
==1780==    by 0x805DA0A: main (in /usr/bin/python2.7)
==1780==  Address 0x49bb010 is 8 bytes before a block of size 303 free'd
==1780==    at 0x402896C: realloc (vg_replace_malloc.c:525)
==1780==    by 0x8064F9B: PyTokenizer_FromString (in /usr/bin/python2.7)
==1780==    by 0x8061CF5: PyParser_ParseStringFlagsFilenameEx (in /usr/bin/python2.7)
==1780==
==1780==
==1780== HEAP SUMMARY:
==1780==     in use at exit: 1,009,521 bytes in 229 blocks
==1780==   total heap usage: 6,958 allocs, 6,729 frees, 6,428,912 bytes allocated
==1780==
==1780== LEAK SUMMARY:
==1780==    definitely lost: 0 bytes in 0 blocks
==1780==    indirectly lost: 0 bytes in 0 blocks
==1780==      possibly lost: 5,684 bytes in 16 blocks
==1780==    still reachable: 1,003,837 bytes in 213 blocks
==1780==         suppressed: 0 bytes in 0 blocks
==1780== Rerun with --leak-check=full to see details of leaked memory
==1780==
==1780== For counts of detected and suppressed errors, rerun with: -v
==1780== Use --track-origins=yes to see where uninitialised values come from
==1780== ERROR SUMMARY: 754 errors from 52 contexts (suppressed: 25 from 6)


Oh, and the script in question?

def main():
    print("Hello World")

if __name__ == '__main__':
    main()

>>10

RAM can be used for better things, like caching files and stuff.

And yes, when a process is terminated, all the memory it was using is returned, regardless of how the program in the running processed decided to allocate data in the memory the OS gave it. So there is no point in freeing memory immediately before the program ends, for example. This type of memory leak isn't really a leak at all, since it was always in use by the program during its execution, and taking the time to free it when the program is terminating isn't needed and would only take needless time.