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| -rw-r--r-- | doc/HACKING | 42 |
1 files changed, 41 insertions, 1 deletions
diff --git a/doc/HACKING b/doc/HACKING index 5d720172f..2f3dd43a0 100644 --- a/doc/HACKING +++ b/doc/HACKING @@ -123,11 +123,51 @@ Note that such a comment will be removed if the git commit option need. If you really need to do it, use a separate commit for such a change. - - C99 syntax should not be used; stick to C90. + - Only certain C99 features may be used (see below); in general + stick to C90. - Please do not use C++ =//= style comments. - Try to fit lines into 80 columns. - Ignore signed/unsigned pointer mismatches - No arithmetic on void pointers; cast to char* first. + - We use our own printf style functions like =es_printf=, and + =es_asprintf= which implement most C99 features with the exception + of =wchar_t= (which should anyway not be used). Please always use + them and do not resort to those provided by libc. The rationale + for using them is that we know that the format specifiers work on + all platforms and that we do not need to chase platform dependent + bugs. + - It is common to have a label named "leave" for a function's + cleanup and return code. This helps with freeing memory and is a + convenient location to set a breakpoint for debugging. + - Always use xfree() instead of free(). If it is not easy to see + that the freed variable is not anymore used, explicitly set the + variable to NULL. + - Init function local variables only if needed so that the compiler + can do a better job in detecting uninitialized variables which may + indicate a problem with the code. + - Never init static or file local variables to 0 to make sure they + end up in BSS. + - Use --enable-maintainer-mode with configure. + +*** C99 language features + + In GnuPG 2.x, but *not in 1.4* and not in most libraries, a limited + set of C99 features may be used: + + - Variadic macros: + : #define foo(a,...) bar(a, __VA_ARGS__) + + - The predefined macro =__func__=: + : log_debug ("%s: Problem with foo\n", __func__); + + - Variable declaration inside a for(): + : for (int i = 0; i < 5; ++) + : bar (i); + + Although we usually make use of the =u16=, =u32=, and =u64= types, + it is also possible to include =<stdint.h>= and use =int16_t=, + =int32_t=, =int64_t=, =uint16_t=, =uint32_t=, and =uint64_t=. But do + not use =int8_t= or =uint8_t=. ** Commit log keywords |