diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/qemu/osdep.h | 29 |
1 files changed, 28 insertions, 1 deletions
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h index 281782d526..e8568a0a54 100644 --- a/include/qemu/osdep.h +++ b/include/qemu/osdep.h @@ -147,8 +147,35 @@ extern int daemon(int, int); #if !defined(ESHUTDOWN) #define ESHUTDOWN 4099 #endif + +/* time_t may be either 32 or 64 bits depending on the host OS, and + * can be either signed or unsigned, so we can't just hardcode a + * specific maximum value. This is not a C preprocessor constant, + * so you can't use TIME_MAX in an #ifdef, but for our purposes + * this isn't a problem. + */ + +/* The macros TYPE_SIGNED, TYPE_WIDTH, and TYPE_MAXIMUM are from + * Gnulib, and are under the LGPL v2.1 or (at your option) any + * later version. + */ + +/* True if the real type T is signed. */ +#define TYPE_SIGNED(t) (!((t)0 < (t)-1)) + +/* The width in bits of the integer type or expression T. + * Padding bits are not supported. + */ +#define TYPE_WIDTH(t) (sizeof(t) * CHAR_BIT) + +/* The maximum and minimum values for the integer type T. */ +#define TYPE_MAXIMUM(t) \ + ((t) (!TYPE_SIGNED(t) \ + ? (t)-1 \ + : ((((t)1 << (TYPE_WIDTH(t) - 2)) - 1) * 2 + 1))) + #ifndef TIME_MAX -#define TIME_MAX LONG_MAX +#define TIME_MAX TYPE_MAXIMUM(time_t) #endif /* HOST_LONG_BITS is the size of a native pointer in bits. */ |