forked from panda-re/panda
-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Document QEMU coding style (v2) (Avi Kivity)
With the help of some Limoncino I noted several aspects of the QEMU coding style, particularly where it differs from the Linux coding style as many contributors work on both projects. Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6976 c046a42c-6fe2-441c-8c8c-71466251a162
- Loading branch information
aliguori
committed
Apr 5, 2009
1 parent
8eca6b1
commit e68b98d
Showing
1 changed file
with
78 additions
and
0 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,78 @@ | ||
Qemu Coding Style | ||
================= | ||
|
||
1. Whitespace | ||
|
||
Of course, the most important aspect in any coding style is whitespace. | ||
Crusty old coders who have trouble spotting the glasses on their noses | ||
can tell the difference between a tab and eight spaces from a distance | ||
of approximately fifteen parsecs. Many a flamewar have been fought and | ||
lost on this issue. | ||
|
||
QEMU indents are four spaces. Tabs are never used, except in Makefiles | ||
where they have been irreversibly coded into the syntax by some moron. | ||
Spaces of course are superior to tabs because: | ||
|
||
- You have just one way to specify whitespace, not two. Ambiguity breeds | ||
mistakes. | ||
- The confusion surrounding 'use tabs to indent, spaces to justify' is gone. | ||
- Tab indents push your code to the right, making your screen seriously | ||
unbalanced. | ||
- Tabs will be rendered incorrectly on editors who are misconfigured not | ||
to use tab stops of eight positions. | ||
- Tabs are rendered badly in patches, causing off-by-one errors in almost | ||
every line. | ||
- It is the QEMU coding style. | ||
|
||
Do not leave whitespace dangling off the ends of lines. | ||
|
||
2. Line width | ||
|
||
Lines are 80 characters; not longer. | ||
|
||
Rationale: | ||
- Some people like to tile their 24" screens with a 6x4 matrix of 80x24 | ||
xterms and use vi in all of them. The best way to punish them is to | ||
let them keep doing it. | ||
- Code and especially patches is much more readable if limited to a sane | ||
line length. Eighty is traditional. | ||
- It is the QEMU coding style. | ||
|
||
3. Naming | ||
|
||
Variables are lower_case_with_underscores; easy to type and read. Structured | ||
type names are in CamelCase; harder to type but standing out. Scalar type | ||
names are lower_case_with_underscores_ending_with_a_t, like the POSIX | ||
uint64_t and family. Note that this last convention contradicts POSIX | ||
and is therefore likely to be changed. | ||
|
||
Typedefs are used to eliminate the redundant 'struct' keyword. It is the | ||
QEMU coding style. | ||
|
||
4. Block structure | ||
|
||
Every indented statement is braced; even if the block contains just one | ||
statement. The opening brace is on the line that contains the control | ||
flow statement that introduces the new block; the closing brace is on the | ||
same line as the else keyword, or on a line by itself if there is no else | ||
keyword. Example: | ||
|
||
if (a == 5) { | ||
printf("a was 5.\n"); | ||
} else if (a == 6) { | ||
printf("a was 6.\n"); | ||
} else { | ||
printf("a was something else entirely.\n"); | ||
} | ||
|
||
An exception is the opening brace for a function; for reasons of tradition | ||
and clarity it comes on a line by itself: | ||
|
||
void a_function(void) | ||
{ | ||
do_something(); | ||
} | ||
|
||
Rationale: a consistent (except for functions...) bracing style reduces | ||
ambiguity and avoids needless churn when lines are added or removed. | ||
Furthermore, it is the QEMU coding style. |