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authorLennart Poettering <lennart@poettering.net>2019-04-12 16:26:46 +0200
committerLennart Poettering <lennart@poettering.net>2019-04-12 16:28:35 +0200
commitf42c1cd4b554ddf622886dcc1cd816c7277df1f4 (patch)
tree19da63e5fae92c56e5d598fb63e5eab41f2000a2 /docs/CODING_STYLE.md
parent971dfffab83de424bc36a3c034aabb04075abd60 (diff)
downloadsystemd-f42c1cd4b554ddf622886dcc1cd816c7277df1f4.tar.gz
CODING_STYLE: move out section about Types
Diffstat (limited to 'docs/CODING_STYLE.md')
-rw-r--r--docs/CODING_STYLE.md70
1 files changed, 35 insertions, 35 deletions
diff --git a/docs/CODING_STYLE.md b/docs/CODING_STYLE.md
index 2c85485fa2..cf6ea668db 100644
--- a/docs/CODING_STYLE.md
+++ b/docs/CODING_STYLE.md
@@ -120,9 +120,6 @@ title: Coding Style
Or in other words, if you use `char buf[256]` then you are likely
doing something wrong!
-- Stay uniform. For example, always use `usec_t` for time
- values. Do not mix `usec` and `msec`, and `usec` and whatnot.
-
- Make use of `_cleanup_free_` and friends. It makes your code much
nicer to read (and shorter)!
@@ -130,12 +127,6 @@ title: Coding Style
numbers. Their syntax is locale dependent (i.e. `5.000` in en_US is
generally understood as 5, while in de_DE as 5000.).
-
-- Unless you allocate an array, `double` is always a better choice
- than `float`. Processors speak `double` natively anyway, so there is
- no speed benefit, and on calls like `printf()` `float`s get promoted
- to `double`s anyway, so there is no point.
-
- Do not mix function invocations with variable definitions in one
line. Wrong:
@@ -161,19 +152,6 @@ title: Coding Style
only jump to the end of a function, and little else. Never jump
backwards!
-- Think about the types you use. If a value cannot sensibly be
- negative, do not use `int`, but use `unsigned`.
-
-- Use `char` only for actual characters. Use `uint8_t` or `int8_t`
- when you actually mean a byte-sized signed or unsigned
- integers. When referring to a generic byte, we generally prefer the
- unsigned variant `uint8_t`. Do not use types based on `short`. They
- *never* make sense. Use `int`, `long`, `long long`, all in
- unsigned and signed fashion, and the fixed-size types
- `uint8_t`, `uint16_t`, `uint32_t`, `uint64_t`, `int8_t`, `int16_t`, `int32_t` and so on,
- as well as `size_t`, but nothing else. Do not use kernel types like
- `u32` and so on, leave that to the kernel.
-
- Public API calls (i.e. functions exported by our shared libraries)
must be marked `_public_` and need to be prefixed with `sd_`. No
other functions should be prefixed like that.
@@ -248,9 +226,6 @@ title: Coding Style
- `F_DUPFD_CLOEXEC` should be used instead of `F_DUPFD`, and so on,
- invocations of `fopen()` should take `e`.
-- Use the bool type for booleans, not integers. One exception: in public
- headers (i.e those in `src/systemd/sd-*.h`) use integers after all, as `bool`
- is C99 and in our public APIs we try to stick to C89 (with a few extension).
- When you invoke certain calls like `unlink()`, or `mkdir_p()` and you
know it is safe to ignore the error it might return (because a later
@@ -343,16 +318,6 @@ title: Coding Style
recommendation is to simply write it without any such expression by
using `for (;;)`.
-- Never use the `off_t` type, and particularly avoid it in public
- APIs. It's really weirdly defined, as it usually is 64-bit and we
- don't support it any other way, but it could in theory also be
- 32-bit. Which one it is depends on a compiler switch chosen by the
- compiled program, which hence corrupts APIs using it unless they can
- also follow the program's choice. Moreover, in systemd we should
- parse values the same way on all architectures and cannot expose
- `off_t` values over D-Bus. To avoid any confusion regarding conversion
- and ABIs, always use simply `uint64_t` directly.
-
- Commit message subject lines should be prefixed with an appropriate
component name of some kind. For example "journal: ", "nspawn: " and
so on.
@@ -475,6 +440,41 @@ title: Coding Style
effect on the regular file. If in doubt consider turning off `O_NONBLOCK` again
after opening.
+## Types
+
+- Think about the types you use. If a value cannot sensibly be negative, do not
+ use `int`, but use `unsigned`.
+
+- Use `char` only for actual characters. Use `uint8_t` or `int8_t` when you
+ actually mean a byte-sized signed or unsigned integers. When referring to a
+ generic byte, we generally prefer the unsigned variant `uint8_t`. Do not use
+ types based on `short`. They *never* make sense. Use `int`, `long`, `long
+ long`, all in unsigned and signed fashion, and the fixed-size types
+ `uint8_t`, `uint16_t`, `uint32_t`, `uint64_t`, `int8_t`, `int16_t`, `int32_t`
+ and so on, as well as `size_t`, but nothing else. Do not use kernel types
+ like `u32` and so on, leave that to the kernel.
+
+- Stay uniform. For example, always use `usec_t` for time values. Do not mix
+ `usec` and `msec`, and `usec` and whatnot.
+
+- Never use the `off_t` type, and particularly avoid it in public APIs. It's
+ really weirdly defined, as it usually is 64-bit and we don't support it any
+ other way, but it could in theory also be 32-bit. Which one it is depends on
+ a compiler switch chosen by the compiled program, which hence corrupts APIs
+ using it unless they can also follow the program's choice. Moreover, in
+ systemd we should parse values the same way on all architectures and cannot
+ expose `off_t` values over D-Bus. To avoid any confusion regarding conversion
+ and ABIs, always use simply `uint64_t` directly.
+
+- Unless you allocate an array, `double` is always a better choice than
+ `float`. Processors speak `double` natively anyway, so there is no speed
+ benefit, and on calls like `printf()` `float`s get promoted to `double`s
+ anyway, so there is no point.
+
+- Use the bool type for booleans, not integers. One exception: in public
+ headers (i.e those in `src/systemd/sd-*.h`) use integers after all, as `bool`
+ is C99 and in our public APIs we try to stick to C89 (with a few extension).
+
## Referencing Concepts
- When referring to a configuration file option in the documentation and such,