Is there a C equivalent of C#'s decimal type?
See the question and my original answer on StackOverflowAs other pointed out, there's nothing in C standard(s) such as .NET's decimal, but, if you're working on Windows and have the Windows SDK, it's defined:
Represents a decimal data type that provides a sign and scale for a number (as in coordinates.)
Decimal variables are stored as 96-bit (12-byte) unsigned integers scaled by a variable power of 10. The power of 10 scaling factor specifies the number of digits to the right of the decimal point, and ranges from 0 to 28.
typedef struct tagDEC {
USHORT wReserved;
union {
struct {
BYTE scale;
BYTE sign;
} DUMMYSTRUCTNAME;
USHORT signscale;
} DUMMYUNIONNAME;
ULONG Hi32;
union {
struct {
ULONG Lo32;
ULONG Mid32;
} DUMMYSTRUCTNAME2;
ULONGLONG Lo64;
} DUMMYUNIONNAME2;
} DECIMAL;
DECIMAL is used to represent an exact numeric value with a fixed precision and fixed scale.
The origin of this type is Windows' COM/OLE automation (introduced for VB/VBA/Macros, etc. so, it predates .NET, which has very good COM automation support), documented here officially: [MS-OAUT]: OLE Automation Protocol, 2.2.26 DECIMAL
It's also one of the VARIANT type (VT_DECIMAL). In x86 architecture, it's size fits right in the VARIANT (16 bytes).