docs/devel/style.rst

9 Please use the script checkpatch.pl in the scripts directory to check
34 * The confusion surrounding 'use tabs to indent, spaces to justify' is gone.
38   to use tab stops of eight positions.
94 that use long function or symbol names. If wrapping the line at 80 columns
105   xterms and use vi in all of them.  The best way to punish them is to
126 A number of short naming conventions exist for variables that use
137 Wrapped version of standard library or GLib functions use a ``qemu_``
159 workarounds we use the suffix ``_compat``. These are generally not
207 of blocks. To avoid accidental re-use it is permissible to declare
242 We use traditional C-style /``*`` ``*``/ comments and avoid // comments.
259 (Some of the existing comments in the codebase use the GNU Coding
313 QEMU makes fairly extensive use of the macro pre-processor to
320 If you do use template header files they should be named with the
327 It should be common sense to use the right type, but we have collected
337 If it's host memory-size related, size_t should be a good choice (use
338 ssize_t only if required). Guest RAM memory offsets must use ram_addr_t,
341 If it's file-size related, use off_t.
342 If it's file-offset related (i.e., signed), use off_t.
343 If it's just counting small numbers use "unsigned int";
347 In the event that you require a specific width, use a standard type
351 Don't use Linux kernel internal types like u32, __u32 or __le32.
353 Use hwaddr for guest physical addresses except pcibus_t
362 vaddr is the best type to use to hold a CPU virtual address in
373 full CPU virtual address in the case of target ABIs which use 32 bit pointers
375 the target's ABI must use this type for anything that on the target is defined
380 to use some system interface that requires a type like size_t, pid_t or
381 off_t, use matching types for any corresponding variables.
383 Also, if you try to use e.g., "unsigned int" as a type, and that
385 it's best just to use the *wrong* type, if "pulling the thread"
413 you can use "include/qemu/typedefs.h" for example.  However, as a matter
414 of convenience it is also perfectly fine to use forward struct
428 Use of the ``malloc/free/realloc/calloc/valloc/memalign/posix_memalign``
430 use the GLib memory allocation routines
446 fall-back to a smaller one if need be we should use functions like
478 Do not use the strncpy function.  As mentioned in the man page, it does *not*
479 guarantee a NULL-terminated buffer, which makes it extremely dangerous to use.
481 use this similar function when possible, but note its different signature:
487 Don't use strcat because it can't check for buffer overflows, but:
493 The same limitation exists with sprintf and vsprintf, so use snprintf and
505 so instead of e.g. isalnum you should use qemu_isalnum.
507 Because of the memory management rules, you must use g_strdup/g_strndup
514 string argument and following "..." in its prototype, be sure to use
544 In addition, QEMU assumes that the compiler does not use the latitude
554 such it has the freedom to make use of a C language extension for
570   by a previous use of G_DEFINE_AUTOPTR_CLEANUP_FUNC. This is
615   otherwise the cleanup function will use uninitialized stack memory
738 Do not use printf(), fprintf() or monitor_printf().  Instead, use
743 Use error_printf() & friends to print additional information.
747 automatically.  To manipulate it manually, use the loc_``*``() from
760 Use the simplest suitable method to communicate success / failure to
770 only the function really knows, use Error ``*````*``, and set suitable errors.
798 In trace-events files, use a '0x' prefix to specify hex numbers, as in:
812 However, you can use '0x' for such groups if you want. Anyway, be sure that
822 to not use '0x' because for some things notations like %x.%x.%x are used not
828 Do not use printf flag '#', like '%#x'.