- Any comments that are added must use `/* */`.
- All comments should start on the same line as the opening `/*`.
- Single-line comments should simply be placed between `/* */`. For example:
- ```
+ ```C
/* Define pivot_root() if missing from the C library */
```
- Multi-line comments should end with the closing `*/` on a separate line. For
example:
- ```
+ ```C
/* At this point the old-root is mounted on top of our new-root
* To unmounted it we must not be chdir()ed into it, so escape back
* to old-root.
- They should be descriptive, without being needlessly long. It is best to just
use already existing error messages as examples.
- Examples of acceptable error messages are:
- ```
+ ```C
SYSERROR("Failed to create directory \"%s\"", path);
WARN("\"/dev\" directory does not exist. Proceeding without autodev being set up");
```
the function in the `*.c` file the function signature should not be preceded
by the `extern` keyword. When declaring the function signature in the `*.h`
file it must be preceded by the `extern` keyword. For example:
- ```
+ ```C
/* Valid function definition in a *.c file */
ssize_t lxc_write_nointr(int fd, const void* buf, size_t count)
{
- put standard types defined by libc before types defined by LXC
- put multiple declarations of the same type on the same line
- Examples of good declarations can be seen in the following function:
- ```
+ ```C
int lxc_clear_procs(struct lxc_conf *c, const char *key)
{
struct lxc_list *it, *next;
single-line conditions. If there is at least one non-single-line
condition `{}` must be used.
- For example:
- ```
+ ```C
/* no brackets needed */
if (size > INT_MAX)
return -EFBIG;
- When checking whether a function not returning booleans was successful or not
the returned value must be assigned before it is checked (`str{n}cmp()`
functions being one notable exception). For example:
- ```
+ ```C
/* assign value to "ret" first */
ret = mount(sourcepath, cgpath, "cgroup", remount_flags, NULL);
/* check whether function was successful */
}
```
Functions returning booleans can be checked directly. For example:
- ```
+ ```C
extern bool lxc_string_in_array(const char *needle, const char **haystack);
/* check right away */
treated as such since they don't really behave like boolean functions. So
`if (!str{n}cmp())` and `if (str{n}cmp())` checks must not be used. Good
examples are found in the following functions:
- ```
+ ```C
static int set_config_hooks(const char *key, const char *value,
struct lxc_conf *lxc_conf, void *data)
- **only** jump downwards unless you are handling `EAGAIN` errors and want to
avoid `do-while` constructs.
- An example of a good usage of `goto` is:
- ```
+ ```C
static int set_config_idmaps(const char *key, const char *value,
struct lxc_conf *lxc_conf, void *data)
{
- If you implement a custom cleanup function to e.g. free a complex type
you declared you must ensure that the object's null type is handled and
treated as a NOOP. For example:
- ```
+ ```C
void lxc_free_array(void **array, lxc_free_fn element_free_fn)
{
void **p;
descriptors and sets the already closed file descriptors to `-EBADF`. On the
next call it can simply check whether the file descriptor is positive and
move on if it isn't:
- ```
+ ```C
static void lxc_put_attach_clone_payload(struct attach_clone_payload *p)
{
if (p->ipc_socket >= 0) {
default do not need to be cast to `(void)`. Classical candidates are
`close()` and `fclose()`.
- A good example is:
- ```
+ ```C
for (i = 0; hierarchies[i]; i++) {
char *fullpath;
char *path = hierarchies[i]->fullcgpath;
- Please always use the affected file (without the file type suffix) or module
as a prefix in the commit message.
- Examples of good commit messages are:
- ```
+ ```Diff
commit b87243830e3b5e95fa31a17cf1bfebe55353bf13
Author: Felix Abecassis <fabecassis@nvidia.com>
Date: Fri Feb 2 06:19:13 2018 -0800
#### Keep Arrays of `struct`s Aligned Horizontally When Initializing
- Arrays of `struct`s are:
- ```
+ ```C
struct foo_struct {
int n;
int m;
- Always leave a single space between the largest member of the current column
and the member in the next column.
- A good example is
- ```
+ ```C
struct signame {
int num;
const char *name;
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