First time here? Check out the FAQ!

Wing Pro 7: Print Function Execution Is Inconsistent

When debugging/stepping over line by line, the first print can always print without any issue. However, from the second print on, none will print until the end of the script. When the last line finished and is executed, the Debug I/O finally prints the missing lines all at once. This seems like a bug for me.

Here's the code example

print("First line prints without any problem")
print("From this line on...")
print("Nothing prints")
print("Until the end of this script/line is executed")

Here are the software/OS versions

  1. Python exe: 3.8.5
  2. OS: Windows 10 Pro
  3. Wing Pro (rev 3600c9873c6f)

Some of my findings:

  1. The same issue perists when using different Python 3 (3.7.x) with the same Wing Pro ( on the same OS (Windows 10 Pro)
  2. The same issue doesn't exist with WingIDE6.1 on the same OS (Windows 10 Pro)
  3. The same issue doesn't exist on my Macbook Pro (macOS Catalina 10.15.6) with Wing Pro (rev 3b2ed12a0484)
asked 2020-09-15 01:27:35 -0500
This post is a wiki. Anyone with karma >75 is welcome to improve it.
edit flag offensive 0 remove flag close merge delete


add a comment see more comments

1 Answer


This may be a bug fixed since the versions you're running. I'm not seeing it with Wing on macOS or Windows and there have been relatively recent fixes to I/O buffering.

Note that if you set Python Options under the Debug/Execute tab of Project Properties then omitting -u may cause this. That tells Python to run in un-buffered mode. We specify that option by default but it's possible for the user to override this.

Please let us know if this does not help.

Wingware Support's avatar
Wingware Support
answered 2020-09-15 09:03:03 -0500
edit flag offensive 0 remove flag delete link


I installed Wing Pro (rev 61efbca05d93) on macOS Catalina 10.15.6 and the problem has been resolved. Thank you for your prompt resolution.

baiyi.tzeng's avatar baiyi.tzeng (2020-09-15 17:40:46 -0500) edit

Great, thanks for confirming that!

Wingware Support's avatar Wingware Support (2020-09-16 09:06:00 -0500) edit
add a comment see more comments

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account. This space is reserved only for answers. If you would like to engage in a discussion, please instead post a comment under the question or an answer that you would like to discuss.

Add Answer