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Diffstat (limited to 'Documentation/CodingGuidelines')
| -rw-r--r-- | Documentation/CodingGuidelines | 51 |
1 files changed, 37 insertions, 14 deletions
diff --git a/Documentation/CodingGuidelines b/Documentation/CodingGuidelines index 9fca21cc5f..9d5c27807a 100644 --- a/Documentation/CodingGuidelines +++ b/Documentation/CodingGuidelines @@ -162,8 +162,6 @@ For shell scripts specifically (not exhaustive): - We do not use \{m,n\}; - - We do not use -E; - - We do not use ? or + (which are \{0,1\} and \{1,\} respectively in BRE) but that goes without saying as these are ERE elements not BRE (note that \? and \+ are not even part @@ -204,10 +202,19 @@ For C programs: by e.g. "echo DEVELOPER=1 >>config.mak". - We try to support a wide range of C compilers to compile Git with, - including old ones. You should not use features from newer C + 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 standard, even if your compiler groks them. - There are a few exceptions to this guideline: + New C99 features have been phased in gradually, if something's new + in C99 but not used yet don't assume that it's safe to use, some + compilers we target have only partial support for it. These are + considered safe to use: + + . 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}; . since early 2012 with e1327023ea, we have been using an enum definition whose last element is followed by a comma. This, like @@ -223,18 +230,24 @@ For C programs: . since early 2021 with 765dc168882, we have been using variadic macros, mostly for printf-like trace and debug macros. - These used to be forbidden, but we have not heard any breakage - report, and they are assumed to be safe. + . since late 2021 with 44ba10d6, we have had variables declared in + the for loop "for (int i = 0; i < 10; i++)". + + New C99 features that we cannot use yet: + + . %z and %zu as a printf() argument for a size_t (the %z being for + the POSIX-specific ssize_t). Instead you should use + printf("%"PRIuMAX, (uintmax_t)v). These days the MSVC version we + rely on supports %z, but the C library used by MinGW does not. + + . Shorthand like ".a.b = *c" in struct initializations is known to + trip up an older IBM XLC version, use ".a = { .b = *c }" instead. + See the 33665d98 (reftable: make assignments portable to AIX xlc + v12.01, 2022-03-28). - Variables have to be declared at the beginning of the block, before the first statement (i.e. -Wdeclaration-after-statement). - - Declaring a variable in the for loop "for (int i = 0; i < 10; i++)" - is still not allowed in this codebase. We are in the process of - allowing it by waiting to see that 44ba10d6 (revision: use C99 - declaration of variable in for() loop, 2021-11-14) does not get - complaints. Let's revisit this around November 2022. - - NULL pointers shall be written as NULL, not as 0. - When declaring pointers, the star sides with the variable @@ -650,8 +663,8 @@ Writing Documentation: (One or more of <file>.) Optional parts are enclosed in square brackets: - [<extra>] - (Zero or one <extra>.) + [<file>...] + (Zero or more of <file>.) --exec-path[=<path>] (Option with an optional argument. Note that the "=" is inside the @@ -665,6 +678,16 @@ Writing Documentation: [-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] + + Don't use spacing around "|" tokens when they're used to seperate the + alternate arguments of an option: + Do: --track[=(direct|inherit)] + Don't: --track[=(direct | inherit)] + Parentheses are used for grouping: [(<rev> | <range>)...] (Any number of either <rev> or <range>. Parens are needed to make |