What's the difference between python3.<x> and python3.<x>m

Question

• What does the m stand for in python3.6m ?
• How does it differ to non m version?
• In which case would I prefer to use python3.6m rather than python3.6?

Solution

What does the m stand for in python3.6m?

It signifies that Python was configured --with-pymalloc which enables a specialized implementation for allocating memory that's faster than the system malloc.

How does it differ to non m version?

The non m version is, obviously, not configured with it.

In which case would I prefer to use python3.6m rather than python3.6?

Probably most usefull when writing C extensions, in general it shouldn't be something you should worry about.

Comments

[Steven Lu]

This answer sounds satisfying, but not when my machine tells me that both executables are exactly 4576440 bytes in size. (pretty clean ubuntu 18.04 server install). I demand to know why they are at least not symlinked to each other. waste of disk. grumble.

[Steven Lu]

And yes they have the same SHA1 hash too.

[Diedre]

i have noticed that they have different header files, that may be the difference

[ratijas]

@StevenLu app may choose to behave differently depending on its invocation name. not sure about this particular case, though

[Kevin Buchs]

if python m is faster, why would one not use that exclusively?

[Martin Tournoij]

@StevenLu On my system they are the same: ls -i python3.7 python3.7m reports 8943110 python3.7 8943110 python3.7m; same inode, so same file. It's a hard link. I presume this is done so that #!/usr/bin/env python3.7m works?

[Steven Lu]

sweet! @MartinTournoij