# String.c question

**URL:** <https://www.ruby-forum.com/t/string-c-question/155582>\
**Category:** Ruby\
**Created:** [December 13, 2008, 11:36pm UTC](https://www.ruby-forum.com/t/string-c-question/155582 "2008-12-13T23:36:59Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![timhunter](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/71e660/32.png) [@timhunter](https://www.ruby-forum.com/u/timhunter)\
**Post date:** [December 13, 2008, 11:36pm UTC](https://www.ruby-forum.com/t/string-c-question/155582/1 "2008-12-13T23:36:59Z")

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How does rb\_str\_cat differ from rb\_str\_buf\_cat?

I have a a String object, a C pointer to a char array, and the length of  
the array. The array is 10KB or even 100KB. I want to cat the char array  
to the String. Which is the better function to use?

---

<div class="post-metadata">

**Author:** ![timhunter](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/71e660/32.png) [@timhunter](https://www.ruby-forum.com/u/timhunter)\
**Post date:** [December 20, 2008, 2:55pm UTC](https://www.ruby-forum.com/t/string-c-question/155582/2 "2008-12-20T14:55:55Z")

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In message “Re: string.c question”  
on Sun, 14 Dec 2008 07:29:17 +0900, Tim H. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
writes:

|How does rb\_str\_cat differ from rb\_str\_buf\_cat?

rb\_str\_buf\_cat() is a function to use with strings created by  
rb\_str\_buf\_new(). If you’re not sure use rb\_str\_cat().

```
          matz.

```