How does it work?

MagNumDB is a database that contains about 360,000 items. These items are constants, names, values all extracted from more than 9,000 header files (.h, .hxx, .hpp, .idl, etc.) provided by standard Windows and Visual Studio SDKs and WDKs.

Some values have been extracted from the very special uuid.lib file that contains the value of thousands of guids and property keys, not present anywhere else in header files. This can explain some duplicates (because names in uuid.lib are not always exactly the same as names in .h parsed files...).

It also contains around 36,0000 undocumented guids that we found ... meeeeep ...


To build this database, we have tried many existing parsers, things like CLANG or other fine tools, but they just don't suit our needs. They can't handle thousands of files that don't compile together, they can't handle some specific (or just very old) Microsoft constructs or annotations, they don't remember the stack of #define directives that led to a definition, they only give you a final AST, not a partial one, etc.

So, in the end, we have written a C/C++ parser named C2P5 (for C/CPP/PreProcessor/Parser), tailored specifically for computing constants. C2P5 is capable of preprocessing, parsing and partially evaluating all header files as if they were included in a one big virtual project (that of course, does not compile) on a 32G RAM machine. It currently supports the following preprocessor and C/C++ constructs:

  • #define preprocessor that define constants
  • #define preprocessor that define expression to compute constants
  • C and C++ constants, strings and enum definitions, and some level of pointerness
  • Special GUID constructs like DECLSPEC_UUID, DEFINE_GUIDSTRUCT, MIDL_INTERFACE, you name it
  • PROPERTYKEY constructs
  • Some IDL constructs
  • Etc.

The parser remembers dynamic preprocessor definitions (#if, #ifdef, etc.) that are conditions for constants definitions and expression computation. All parsed items are saved in the database, as well as the associated conditions. There may be more than one item corresponding to a given name, if there are differences in their associated conditions stack.

C2P5 supports the following types of constants, regardless of the way they are defined in source files:

  • integer, signed or unsigned, from 8-bit to 128-bit
  • floating point number, single (32-bit) or double (64-bit)
  • globally unique identifier, or guid, uuid, CLSID, IID, etc.
  • string, in narrow, wide, or utf-8/16/32 formats
  • character, in narrow, wide, or utf-8/16/32 formats
  • pointer, a constant cast as a pointer
  • property key, or PROPERTYKEY, or PKEY, a combination of a guid (fmtid) and a 32-bit integer (id).

 Powered by

C2P5 and this MagNumDB web site are written in C# and use a Lucene database as a full-text search engine. C2P5 uses a custom ANTLR4cs C grammar for expression parsing, not for preprocessor parsing.


 Frequently Asked Questions

  • Q: Can I run custom queries?
    A: Yes. You can use Lucene's query syntax. Note the Database is case insensitive. Check out the list of columns with their corresponding database column names:

    • Index: the item's index.
    • Name: the item's name, or title. For enum values, it's prefixed with the enum's name.
      Corresponding database field: title.
    • Type: the item's type, expressed in a specific, universal system.
      Corresponding database's field: valuetype, but use the value of the Storage type column for queries on items type.
    • Value: the item's value. For string values, it's displayed as is w/o quotes nor escaping.
      Corresponding database field: value. There is also a typedvalue field that can contain database's Int32, Int64, Float, Double or String typed values.
    • Hex Value: the item's hexadecimal value, only valid for integer types.
      There is no corresponding database field.
    • Signed Value: the item's signed value, only valid for integer and double types. Useful when you found a unsigned number and want to get the corresponding signed value (uint -> int for example).
      There is no corresponding database field.
    • Source lines(s): the source lines from which the item was extracted. Comments and characters such as TAB, CR are preserved.
      Corresponding database field: source.
    • File path: the file path from which the item was extracted, terminated by the line index.
      Corresponding database field: filepath. There are also directory and filename fields. filename is useful to query for values in a given file.
    • Score: Database's score value. Items are returned sorted by score.
    • Guid formats: a utility columns that proposes all possible guid formats. Only valid for guid types.
      There is no corresponding database field
    • Char type: the character encoding (narrow, wide, etc.). Only valid for char and string values.
      Corresponding database field: chartype.
    • Storage type: the exact storage type in the database. Only used for specific queries.
      Corresponding database field: valuetype.
    • Conditions: the list of preprocessor conditions for a given item. If a condition is surrounded with a REVERSE function, it means the reverse condition of what's surrounded was the condition.
      Corresponding database field: conditions. There may be multiple conditions fields for one item.

    Some important points to note:

    • If you search for a negative number (like error codes expressed using signed integers), you can surround the search with double quotes, for example searching for "-2147009290" is equivalent to searching for 0x80073CF6, 80073CF6 (or even 3CF6 in this specific case). If you don't surround negative numbers with double quotes, the system will search for signed and unsigned corresponding values.
    • The full-text search uses items' name, value, hex value, guid formats, source lines, etc. so refine your search if you get back too many items.
    • You can search for guid binary values using just a part of their full definition. For example, if you search for '79eac9c5', it will get you 3 guid entries
    • Leading wild card search (*whatever) is allowed, but it may slow down the search significantly.

    Here are some example or custom queries:

    title:wm_user returns the WM_USER Windows message item, not all items that reference the WM_USER token.

    title:wm_u* returns all items (Windows messages probably) whose name starts with WM_U*.

    value:1024 AND title:wm_* returns all items (Windows messages probably) whose name starts with WM_U* and value is 1024. Note AND must be UPPERCASE for database to understand it as an AND operator.

    value:"00000002-0000-0000-C000-000000000046" returns the IMalloc IID guid value.

  • Q: I always get back 400 items at most. Why?
    A: The MagNumDb site currently limits the number of returned items to this value by design. This should be enough for most real search scenarios (like enums with a big list of values).

  • Q: Some values are empty. Why?
    A: The expression evaluator cannot always compute the final value, because it sometimes require contextual information (custom defines, compiler architecture, etc.) that the parser doesn't have at parsing time. You can enable the Source line(s) column to check what's the corresponding source and try to work it out by yourself. The origin file path and line number is also included.

  • Q: Can I get all values for a given enum?
    A: Sure. For example, __VSHPROPID is the name of an enum, and a query like this: parent:__VSHPROPID will get all the enum's values (66 entries).

  • Q: I sometimes get back items whose name starts with "__magnumdb__enum_". Why?
    A: C allows unnamed enums. The MagNumDb parser just gives them a name, using the defining file name and a counter.

  • Q: I sometimes get back the same item/name twice or more with different values. For example:  TARGET_IS_NT60_OR_LATER. Why?
    A: This can be the case with defines. Their value may be different if they were surrounded by # directives (#if, #else, etc.) in the original source code. You can enable the Condition(s) column to check what are the corresponding conditions for a given item.
    Note: if a condition is surrounded with a funny REVERSE function token, it means the reverse condition of what's surrounded.

  • Q: I can't connect from an IP address but from another one, it works. Why?
    A: The server is constantly monitored for excessive usage. It's possible your IP address has been banned because massive sets of queries where observed. If you think this is an error, send us an email.

 Database Metrics

  • Last update date: Thursday October 7, 2021
  • Items count: 362743
  • Parsed files count: 9541
  • Windows SDK version: 10.0.22000.0
  • NetFx SDK version: 4.8
  • MSVC Tools version: 14.29.30133

 Rest API

There is a JSON version API (you will have to figure out the schema, it's pretty obvious) that you can call here (the search query is the 'q' parameter):

Note this API also has a 400 items maximum limit and the server is monitored for excessive usage (the key can be removed without notice). If you want to get a key, send us an email.



We welcome feedback.
Seen anything missing? A bug? A wrong value? Do you have any suggestion for improvements? Do you have an idea for a cool new feature?

Please contact us here

 About MagNumDB

MagNumDB  2017-2021 Simon Mourier V1.4.0. All rights reserved.

Profile for Simon Mourier at Stack Overflow, Q&A for professional and enthusiast programmers

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All values, names, source code fragments displayed here have been extracted from files that are property of their respective owners.


Index Score Name Type Value Hex value Signed value Guid formats Char type Storage type Source line(s) File path Condition(s)
Index Score Name Type Value Hex value Signed value Guid formats Char type Storage type Source line(s) File path Condition(s)
1 4.491131 STORAGE_MEDIA_TYPE::ABL_5_WO Int32 64 0x00000040 64 System.Int32
ABL_5_WO,                  // Opt_Disk - Ablative 5.25" Write Once Optical
%ProgramFiles(x86)%\Windows Kits\10\Include\10.0.22000.0\um\winioctl.h(866,0)
2 0.6946865 STORAGE_MEDIA_TYPE Enum
typedef enum _STORAGE_MEDIA_TYPE {

    DDS_4mm = 0x20,            // Tape - DAT DDS1,2,... (all vendors)
    MiniQic,                   // Tape - miniQIC Tape
    Travan,                    // Tape - Travan TR-1,2,3,...
    QIC,                       // Tape - QIC
    MP_8mm,                    // Tape - 8mm Exabyte Metal Particle
    AME_8mm,                   // Tape - 8mm Exabyte Advanced Metal Evap
    AIT1_8mm,                  // Tape - 8mm Sony AIT
    DLT,                       // Tape - DLT Compact IIIxt, IV
    NCTP,                      // Tape - Philips NCTP
    IBM_3480,                  // Tape - IBM 3480
    IBM_3490E,                 // Tape - IBM 3490E
    IBM_Magstar_3590,          // Tape - IBM Magstar 3590
    IBM_Magstar_MP,            // Tape - IBM Magstar MP
    STK_DATA_D3,               // Tape - STK Data D3
    SONY_DTF,                  // Tape - Sony DTF
    DV_6mm,                    // Tape - 6mm Digital Video
    DMI,                       // Tape - Exabyte DMI and compatibles
    SONY_D2,                   // Tape - Sony D2S and D2L
    CLEANER_CARTRIDGE,         // Cleaner - All Drive types that support Drive Cleaners
    CD_ROM,                    // Opt_Disk - CD
    CD_R,                      // Opt_Disk - CD-Recordable (Write Once)
    CD_RW,                     // Opt_Disk - CD-Rewriteable
    DVD_ROM,                   // Opt_Disk - DVD-ROM
    DVD_R,                     // Opt_Disk - DVD-Recordable (Write Once)
    DVD_RW,                    // Opt_Disk - DVD-Rewriteable
    MO_3_RW,                   // Opt_Disk - 3.5" Rewriteable MO Disk
    MO_5_WO,                   // Opt_Disk - MO 5.25" Write Once
    MO_5_RW,                   // Opt_Disk - MO 5.25" Rewriteable (not LIMDOW)
    MO_5_LIMDOW,               // Opt_Disk - MO 5.25" Rewriteable (LIMDOW)
    PC_5_WO,                   // Opt_Disk - Phase Change 5.25" Write Once Optical
    PC_5_RW,                   // Opt_Disk - Phase Change 5.25" Rewriteable
    PD_5_RW,                   // Opt_Disk - PhaseChange Dual Rewriteable
    ABL_5_WO,                  // Opt_Disk - Ablative 5.25" Write Once Optical
    PINNACLE_APEX_5_RW,        // Opt_Disk - Pinnacle Apex 4.6GB Rewriteable Optical
    SONY_12_WO,                // Opt_Disk - Sony 12" Write Once
    PHILIPS_12_WO,             // Opt_Disk - Philips/LMS 12" Write Once
    HITACHI_12_WO,             // Opt_Disk - Hitachi 12" Write Once
    CYGNET_12_WO,              // Opt_Disk - Cygnet/ATG 12" Write Once
    KODAK_14_WO,               // Opt_Disk - Kodak 14" Write Once
    MO_NFR_525,                // Opt_Disk - Near Field Recording (Terastor)
    NIKON_12_RW,               // Opt_Disk - Nikon 12" Rewriteable
    IOMEGA_ZIP,                // Mag_Disk - Iomega Zip
    IOMEGA_JAZ,                // Mag_Disk - Iomega Jaz
    SYQUEST_EZ135,             // Mag_Disk - Syquest EZ135
    SYQUEST_EZFLYER,           // Mag_Disk - Syquest EzFlyer
    SYQUEST_SYJET,             // Mag_Disk - Syquest SyJet
    AVATAR_F2,                 // Mag_Disk - 2.5" Floppy
    MP2_8mm,                   // Tape - 8mm Hitachi
    DST_S,                     // Ampex DST Small Tapes
    DST_M,                     // Ampex DST Medium Tapes
    DST_L,                     // Ampex DST Large Tapes
    VXATape_1,                 // Ecrix 8mm Tape
    VXATape_2,                 // Ecrix 8mm Tape
    STK_EAGLE,                 // STK Eagle
    STK_9840,                  // STK 9840
    LTO_Ultrium,               // IBM, HP, Seagate LTO Ultrium
    LTO_Accelis,               // IBM, HP, Seagate LTO Accelis
    DVD_RAM,                   // Opt_Disk - DVD-RAM
    AIT_8mm,                   // AIT2 or higher
    ADR_1,                     // OnStream ADR Mediatypes
    STK_9940,                  // STK 9940
    SAIT,                      // SAIT Tapes
    VXATape                    // VXA (Ecrix 8mm) Tape
%ProgramFiles(x86)%\Windows Kits\10\Include\10.0.22000.0\um\winioctl.h(804,0)