Oren Eini

aka Ayende Rahien

Oren Eini

CEO of RavenDB

a NoSQL Open Source Document Database

Get in touch with me:

oren@ravendb.net +972 52-548-6969

Posts: 7,575
|
Comments: 51,195

Copyright ©️ Ayende Rahien 2004 — 2025

Privacy Policy · Terms
filter by tags archive
stack view grid view
  • architecture (606) rss
  • bugs (450) rss
  • challanges (123) rss
  • community (377) rss
  • databases (481) rss
  • design (893) rss
  • development (640) rss
  • hibernating-practices (71) rss
  • miscellaneous (592) rss
  • performance (397) rss
  • programming (1085) rss
  • raven (1442) rss
  • ravendb.net (526) rss
  • reviews (184) rss
  • 2025
    • May (7)
    • April (10)
    • March (10)
    • February (7)
    • January (12)
  • 2024
    • December (3)
    • November (2)
    • October (1)
    • September (3)
    • August (5)
    • July (10)
    • June (4)
    • May (6)
    • April (2)
    • March (8)
    • February (2)
    • January (14)
  • 2023
    • December (4)
    • October (4)
    • September (6)
    • August (12)
    • July (5)
    • June (15)
    • May (3)
    • April (11)
    • March (5)
    • February (5)
    • January (8)
  • 2022
    • December (5)
    • November (7)
    • October (7)
    • September (9)
    • August (10)
    • July (15)
    • June (12)
    • May (9)
    • April (14)
    • March (15)
    • February (13)
    • January (16)
  • 2021
    • December (23)
    • November (20)
    • October (16)
    • September (6)
    • August (16)
    • July (11)
    • June (16)
    • May (4)
    • April (10)
    • March (11)
    • February (15)
    • January (14)
  • 2020
    • December (10)
    • November (13)
    • October (15)
    • September (6)
    • August (9)
    • July (9)
    • June (17)
    • May (15)
    • April (14)
    • March (21)
    • February (16)
    • January (13)
  • 2019
    • December (17)
    • November (14)
    • October (16)
    • September (10)
    • August (8)
    • July (16)
    • June (11)
    • May (13)
    • April (18)
    • March (12)
    • February (19)
    • January (23)
  • 2018
    • December (15)
    • November (14)
    • October (19)
    • September (18)
    • August (23)
    • July (20)
    • June (20)
    • May (23)
    • April (15)
    • March (23)
    • February (19)
    • January (23)
  • 2017
    • December (21)
    • November (24)
    • October (22)
    • September (21)
    • August (23)
    • July (21)
    • June (24)
    • May (21)
    • April (21)
    • March (23)
    • February (20)
    • January (23)
  • 2016
    • December (17)
    • November (18)
    • October (22)
    • September (18)
    • August (23)
    • July (22)
    • June (17)
    • May (24)
    • April (16)
    • March (16)
    • February (21)
    • January (21)
  • 2015
    • December (5)
    • November (10)
    • October (9)
    • September (17)
    • August (20)
    • July (17)
    • June (4)
    • May (12)
    • April (9)
    • March (8)
    • February (25)
    • January (17)
  • 2014
    • December (22)
    • November (19)
    • October (21)
    • September (37)
    • August (24)
    • July (23)
    • June (13)
    • May (19)
    • April (24)
    • March (23)
    • February (21)
    • January (24)
  • 2013
    • December (23)
    • November (29)
    • October (27)
    • September (26)
    • August (24)
    • July (24)
    • June (23)
    • May (25)
    • April (26)
    • March (24)
    • February (24)
    • January (21)
  • 2012
    • December (19)
    • November (22)
    • October (27)
    • September (24)
    • August (30)
    • July (23)
    • June (25)
    • May (23)
    • April (25)
    • March (25)
    • February (28)
    • January (24)
  • 2011
    • December (17)
    • November (14)
    • October (24)
    • September (28)
    • August (27)
    • July (30)
    • June (19)
    • May (16)
    • April (30)
    • March (23)
    • February (11)
    • January (26)
  • 2010
    • December (29)
    • November (28)
    • October (35)
    • September (33)
    • August (44)
    • July (17)
    • June (20)
    • May (53)
    • April (29)
    • March (35)
    • February (33)
    • January (36)
  • 2009
    • December (37)
    • November (35)
    • October (53)
    • September (60)
    • August (66)
    • July (29)
    • June (24)
    • May (52)
    • April (63)
    • March (35)
    • February (53)
    • January (50)
  • 2008
    • December (58)
    • November (65)
    • October (46)
    • September (48)
    • August (96)
    • July (87)
    • June (45)
    • May (51)
    • April (52)
    • March (70)
    • February (43)
    • January (49)
  • 2007
    • December (100)
    • November (52)
    • October (109)
    • September (68)
    • August (80)
    • July (56)
    • June (150)
    • May (115)
    • April (73)
    • March (124)
    • February (102)
    • January (68)
  • 2006
    • December (95)
    • November (53)
    • October (120)
    • September (57)
    • August (88)
    • July (54)
    • June (103)
    • May (89)
    • April (84)
    • March (143)
    • February (78)
    • January (64)
  • 2005
    • December (70)
    • November (97)
    • October (91)
    • September (61)
    • August (74)
    • July (92)
    • June (100)
    • May (53)
    • April (42)
    • March (41)
    • February (84)
    • January (31)
  • 2004
    • December (49)
    • November (26)
    • October (26)
    • September (6)
    • April (10)
RavenDB Workshops - Deep dive into practical use of Document Data Modeling
  previous post next post  
Aug 04 2013

Reasons to hate C/C++ work

time to read 1 min | 57 words

The following code won’t link. For fun, the set_mapsize and set_flags are both defined in the same file. Both for .h & .c, and the set_mapsize works just fine.

image

Tweet Share Share 19 comments
Tags:
  • bugs

  previous post next post  

Comments

tobi
04 Aug 2013
13:01 PM
tobi

I never understood why the header-based link system is needed. .NET and Java don't need them either, and they work much better.

Ayende Rahien
04 Aug 2013
13:22 PM
Ayende Rahien

tobi, They are needed because this way, you could write a single pass compiler. It meant very little memory was needed to actually do the compilation

eti
04 Aug 2013
14:37 PM
eti

Maybe the pre-processor conditionaly stripps the definition away?

Ayende Rahien
04 Aug 2013
14:47 PM
Ayende Rahien

Eti, Nope, I made sure of that.

zdeslav
04 Aug 2013
14:50 PM
zdeslav

Does dumpbin show the correct symbol in corresponding obj file?

Ayende Rahien
04 Aug 2013
15:03 PM
Ayende Rahien

D:\Work\lightningdb-win\liblmdb\Release [master +10 ~5 -0 !]> &"C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\b in\amd64\dumpbin.exe" /EXPORTS .\mdb.obj Microsoft (R) COFF/PE Dumper Version 11.00.50727.1 Copyright (C) Microsoft Corporation. All rights reserved.

Dump of file .\mdb.obj

File Type: ANONYMOUS OBJECT D:\Work\lightningdb-win\liblmdb\Release [master +10 ~5 -0 !]>

zdeslav
04 Aug 2013
15:21 PM
zdeslav

are you building with /GL option? also, try /SYMBOLS instead of /EXPORTS.

Ayende Rahien
04 Aug 2013
15:29 PM
Ayende Rahien

zdeslav, I am looking at you now with glazed eyes. No idea what you are talking about.

zdeslav
04 Aug 2013
15:42 PM
zdeslav

sorry for succinctness, I was typing with child in my arms :)

i see that you call 'dumpbin /exports' but 'dumpbin /symbols' will list all the symbols, so you can check whether there is anything similar to mdb_env_set_flags, or is it missing completely.

I ask about /GL flag, as it prevents using these flags.

Ayende Rahien
04 Aug 2013
15:47 PM
Ayende Rahien

I removed /GL flag, and then used /symbols. The object has _mdb_env_set_flags in it.

zdeslav
04 Aug 2013
16:06 PM
zdeslav

hmm, markdown is messing up the formatting and stripping underscores. I understand that the symbol name in the obj file starts with the underscore, like _mdb_env_set_flags, without any additions (like @12)? In that case it all seems fine. it's a long shot, but are you sure that set_mapsize is linked from the same obj file and not some other?

Keith
04 Aug 2013
21:04 PM
Keith

those (env, ....)

I'm guessing they should be (&env, ....)

Ayende Rahien
04 Aug 2013
21:20 PM
Ayende Rahien

Keith, No, that is already a pointer.

Keith
04 Aug 2013
21:23 PM
Keith

what do the 3 warnings say?

Alois Kraus
04 Aug 2013
21:39 PM
Alois Kraus

Maybe you have duplicate header files with different content? Check from where the header file is loaded for all projects. Could it be that set_flags does contain as input types ifdefed types which do change the actual signature? That would make it possible to compile it but fail at link time because the library was compiled with a differen set of ifdefs.

Kelly Sommers
05 Aug 2013
03:34 AM
Kelly Sommers

Not enough details in this post to even suggest what the real problem is since I can't see what the project includes.

You need to have midl.h and midl.c in the project. Are they included?

Ayende Rahien
05 Aug 2013
04:13 AM
Ayende Rahien

Kelly, That was mostly to vent. I work around that since I just needed to test something out. FWIW, this was in the lmdb-win project.

Jono
05 Aug 2013
09:50 AM
Jono

The missing symbol is prefixed with a "_" unlike your usage?

Rodrigo Zechin
05 Aug 2013
12:31 PM
Rodrigo Zechin

The fact that both functions are defined in the same header doesn't mean they are implemented in the same library.

You need to find out on which *.lib file this function is implemented and reference it during the linking phase. The easiest (but ugliest) way of doing this is with a #pragma comment(lib, “xxx.lib”) on your *.c file

The "right" way would be to add the lib to your "Additional Dependencies" list on the project properties

Comment preview

Comments have been closed on this topic.

Markdown formatting

ESC to close

Markdown turns plain text formatting into fancy HTML formatting.

Phrase Emphasis

*italic*   **bold**
_italic_   __bold__

Links

Inline:

An [example](http://url.com/ "Title")

Reference-style labels (titles are optional):

An [example][id]. Then, anywhere
else in the doc, define the link:
  [id]: http://example.com/  "Title"

Images

Inline (titles are optional):

![alt text](/path/img.jpg "Title")

Reference-style:

![alt text][id]
[id]: /url/to/img.jpg "Title"

Headers

Setext-style:

Header 1
========
Header 2
--------

atx-style (closing #'s are optional):

# Header 1 #
## Header 2 ##
###### Header 6

Lists

Ordered, without paragraphs:

1.  Foo
2.  Bar

Unordered, with paragraphs:

*   A list item.
    With multiple paragraphs.
*   Bar

You can nest them:

*   Abacus
    * answer
*   Bubbles
    1.  bunk
    2.  bupkis
        * BELITTLER
    3. burper
*   Cunning

Blockquotes

> Email-style angle brackets
> are used for blockquotes.
> > And, they can be nested.
> #### Headers in blockquotes
> 
> * You can quote a list.
> * Etc.

Horizontal Rules

Three or more dashes or asterisks:

---
* * *
- - - - 

Manual Line Breaks

End a line with two or more spaces:

Roses are red,   
Violets are blue.

Fenced Code Blocks

Code blocks delimited by 3 or more backticks or tildas:

```
This is a preformatted
code block
```

Header IDs

Set the id of headings with {#<id>} at end of heading line:

## My Heading {#myheading}

Tables

Fruit    |Color
---------|----------
Apples   |Red
Pears	 |Green
Bananas  |Yellow

Definition Lists

Term 1
: Definition 1
Term 2
: Definition 2

Footnotes

Body text with a footnote [^1]
[^1]: Footnote text here

Abbreviations

MDD <- will have title
*[MDD]: MarkdownDeep

 

FUTURE POSTS

No future posts left, oh my!

RECENT SERIES

  1. RavenDB News (2):
    02 May 2025 - May 2025
  2. Recording (15):
    30 Apr 2025 - Practical AI Integration with RavenDB
  3. Production Postmortem (52):
    07 Apr 2025 - The race condition in the interlock
  4. RavenDB (13):
    02 Apr 2025 - .NET Aspire integration
  5. RavenDB 7.1 (6):
    18 Mar 2025 - One IO Ring to rule them all
View all series

RECENT COMMENTS

  • Scooletz, Yes, we look at other stuff. Most of those are _not_ allowing you to build themselves incrementally nor are they...
    By Oren Eini on Scaling HNSW in RavenDB: Optimizing for inadequate hardware
  • Have you considered other approaches, DiskSpan, Spann etc.? HNSW, as far as I know, is terrible in regards to updates and det...
    By Scooletz on Scaling HNSW in RavenDB: Optimizing for inadequate hardware
  • Steve, The check is for _equality_ - if the current version matches the value in the versions array. When the `_version` ...
    By Oren Eini on Optimizing the cost of clearing a set
  • I'm not following that part, the first 65K times (until ushort.MaxValue) it will be smaller so you'll enter the if/return, bu...
    By Steve on Optimizing the cost of clearing a set
  • Steve, No, I don't need to. It is going to wrap around anyway, after all
    By Oren Eini on Optimizing the cost of clearing a set

Syndication

Main feed Feed Stats
Comments feed   Comments Feed Stats
}