# What does "w+" mean in IO.open?

**URL:** <https://www.ruby-forum.com/t/what-does-w-mean-in-io-open/181224>\
**Category:** Ruby\
**Created:** [January 7, 2010, 3:42pm UTC](https://www.ruby-forum.com/t/what-does-w-mean-in-io-open/181224 "2010-01-07T15:42:26Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![ISSSSaki\_Baz\_C](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/51bf81/32.png) [@ISSSSaki\_Baz\_C](https://www.ruby-forum.com/u/ISSSSaki_Baz_C)\
**Post date:** [January 7, 2010, 3:42pm UTC](https://www.ruby-forum.com/t/what-does-w-mean-in-io-open/181224/1 "2010-01-07T15:42:26Z")

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Hi, the rdoc says that “w+” means:

“w+”: Read-write, truncates existing file to zero length or creates a  
new file for reading and writing.

however in a post I’ve read:

output = open(“my\_pipe”, “w+”) # the w+ means we don’t block

Is it true? AFAIK it’s not correct as you open a IO and later use  
bocking or  
non-blocking methods. Do I miss something?

Thanks.

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**Author:** ![ISSSSaki\_Baz\_C](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/51bf81/32.png) [@ISSSSaki\_Baz\_C](https://www.ruby-forum.com/u/ISSSSaki_Baz_C)\
**Post date:** [January 7, 2010, 7:11pm UTC](https://www.ruby-forum.com/t/what-does-w-mean-in-io-open/181224/2 "2010-01-07T19:11:25Z")

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On 01/07/2010 03:41 PM, Iñaki Baz C. wrote:

> non-blocking methods. Do I miss something?  
> No. RI is RIght. 😉

Kind regards

robert