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Diffstat (limited to 'Documentation/CodingGuidelines')
| -rw-r--r-- | Documentation/CodingGuidelines | 114 |
1 files changed, 85 insertions, 29 deletions
diff --git a/Documentation/CodingGuidelines b/Documentation/CodingGuidelines index 5edd3a0b9d..30fda4142c 100644 --- a/Documentation/CodingGuidelines +++ b/Documentation/CodingGuidelines @@ -241,6 +241,16 @@ For C programs: - We use tabs to indent, and interpret tabs as taking up to 8 spaces. + - Nested C preprocessor directives are indented after the hash by one + space per nesting level. + + #if FOO + # include <foo.h> + # if BAR + # include <bar.h> + # endif + #endif + - We try to keep to at most 80 characters per line. - As a Git developer we assume you have a reasonably modern compiler @@ -248,6 +258,14 @@ For C programs: ensure your patch is clear of all compiler warnings we care about, by e.g. "echo DEVELOPER=1 >>config.mak". + - When using DEVELOPER=1 mode, you may see warnings from the compiler + like "error: unused parameter 'foo' [-Werror=unused-parameter]", + which indicates that a function ignores its argument. If the unused + parameter can't be removed (e.g., because the function is used as a + callback and has to match a certain interface), you can annotate + the individual parameters with the UNUSED (or MAYBE_UNUSED) + keyword, like "int foo UNUSED". + - We try to support a wide range of C compilers to compile Git with, including old ones. As of Git v2.35.0 Git requires C99 (we check "__STDC_VERSION__"). You should not use features from a newer C @@ -261,7 +279,7 @@ For C programs: . since around 2007 with 2b6854c863a, we have been using initializer elements which are not computable at load time. E.g.: - const char *args[] = {"constant", variable, NULL}; + const char *args[] = { "constant", variable, NULL }; . since early 2012 with e1327023ea, we have been using an enum definition whose last element is followed by a comma. This, like @@ -567,6 +585,42 @@ For C programs: use your own debugger and arguments. Example: `GIT_DEBUGGER="ddd --gdb" ./bin-wrappers/git log` (See `wrap-for-bin.sh`.) + - The primary data structure that a subsystem 'S' deals with is called + `struct S`. Functions that operate on `struct S` are named + `S_<verb>()` and should generally receive a pointer to `struct S` as + first parameter. E.g. + + struct strbuf; + + void strbuf_add(struct strbuf *buf, ...); + + void strbuf_reset(struct strbuf *buf); + + is preferred over: + + struct strbuf; + + void add_string(struct strbuf *buf, ...); + + void reset_strbuf(struct strbuf *buf); + + - There are several common idiomatic names for functions performing + specific tasks on a structure `S`: + + - `S_init()` initializes a structure without allocating the + structure itself. + + - `S_release()` releases a structure's contents without freeing the + structure. + + - `S_clear()` is equivalent to `S_release()` followed by `S_init()` + such that the structure is directly usable after clearing it. When + `S_clear()` is provided, `S_init()` shall not allocate resources + that need to be released again. + + - `S_free()` releases a structure's contents and frees the + structure. + For Perl programs: - Most of the C guidelines above apply. @@ -774,78 +828,80 @@ Markup: _<new-branch-name>_ _<template-directory>_ - A placeholder is not enclosed in backticks, as it is not a literal. - When needed, use a distinctive identifier for placeholders, usually made of a qualification and a type: _<git-dir>_ _<key-id>_ - When literal and placeholders are mixed, each markup is applied for - each sub-entity. If they are stuck, a special markup, called - unconstrained formatting is required. - Unconstrained formating for placeholders is __<like-this>__ - Unconstrained formatting for literal formatting is ++like this++ - `--jobs` _<n>_ - ++--sort=++__<key>__ - __<directory>__++/.git++ - ++remote.++__<name>__++.mirror++ + Git's Asciidoc processor has been tailored to treat backticked text + as complex synopsis. When literal and placeholders are mixed, you can + use the backtick notation which will take care of correctly typesetting + the content. + `--jobs <n>` + `--sort=<key>` + `<directory>/.git` + `remote.<name>.mirror` + `ssh://[<user>@]<host>[:<port>]/<path-to-git-repo>` - caveat: ++ unconstrained format is not verbatim and may expand - content. Use Asciidoc escapes inside them. +As a side effect, backquoted placeholders are correctly typeset, but +this style is not recommended. Synopsis Syntax - Syntax grammar is formatted neither as literal nor as placeholder. + The synopsis (a paragraph with [synopsis] attribute) is automatically + formatted by the toolchain and does not need typesetting. A few commented examples follow to provide reference when writing or modifying command usage strings and synopsis sections in the manual pages: Possibility of multiple occurrences is indicated by three dots: - _<file>_... + <file>... (One or more of <file>.) Optional parts are enclosed in square brackets: - [_<file>_...] + [<file>...] (Zero or more of <file>.) - ++--exec-path++[++=++__<path>__] + An optional parameter needs to be typeset with unconstrained pairs + [<repository>] + + --exec-path[=<path>] (Option with an optional argument. Note that the "=" is inside the brackets.) - [_<patch>_...] + [<patch>...] (Zero or more of <patch>. Note that the dots are inside, not outside the brackets.) Multiple alternatives are indicated with vertical bars: - [`-q` | `--quiet`] - [`--utf8` | `--no-utf8`] + [-q | --quiet] + [--utf8 | --no-utf8] Use spacing around "|" token(s), but not immediately after opening or before closing a [] or () pair: - Do: [`-q` | `--quiet`] - Don't: [`-q`|`--quiet`] + Do: [-q | --quiet] + Don't: [-q|--quiet] Don't use spacing around "|" tokens when they're used to separate the alternate arguments of an option: - Do: ++--track++[++=++(`direct`|`inherit`)]` - Don't: ++--track++[++=++(`direct` | `inherit`)] + Do: --track[=(direct|inherit)] + Don't: --track[=(direct | inherit)] Parentheses are used for grouping: - [(_<rev>_ | _<range>_)...] + [(<rev>|<range>)...] (Any number of either <rev> or <range>. Parens are needed to make it clear that "..." pertains to both <rev> and <range>.) - [(`-p` _<parent>_)...] + [(-p <parent>)...] (Any number of option -p, each with one <parent> argument.) - `git remote set-head` _<name>_ (`-a` | `-d` | _<branch>_) + git remote set-head <name> (-a|-d|<branch>) (One and only one of "-a", "-d" or "<branch>" _must_ (no square brackets) be provided.) And a somewhat more contrived example: - `--diff-filter=[(A|C|D|M|R|T|U|X|B)...[*]]` + --diff-filter=[(A|C|D|M|R|T|U|X|B)...[*]] Here "=" is outside the brackets, because "--diff-filter=" is a valid usage. "*" has its own pair of brackets, because it can (optionally) be specified only when one or more of the letters is |