DOCUMENT:Q121460 08-AUG-2001 [winnt] TITLE :Common Object File Format (COFF) PRODUCT :Microsoft Windows NT PROD/VER::; winnt:3.5 OPER/SYS: KEYWORDS:kbOSWinNT310 kbOSWinNT351 ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server version 3.1 - Microsoft Windows NT Workstation version 3.1 - Microsoft Windows NT Advanced Server - Microsoft Windows NT Workstation version 3.5 - Microsoft Windows NT Server version 3.5 ------------------------------------------------------------------------------- SUMMARY ======= Windows NT uses a special format for the executable (image) files and object files. The format used in these files are referred to as Portable Executable (PE) or Common Object File Format (COFF) files. The name Portable Executable refers to the fact that executable files can run on more than one platform. This article describes in detail the internal features of PE/COFF file formats and its parameters. MORE INFORMATION ================ The PE/COFF file headers consist of a MS-DOS stub, file signature, COFF Header, and Optional Header. An object file contains only the COFF Header, but an image file contains all the headers described above. The most important of these headers is the COFF header. The table below describes the information stored in the COFF header. Offset Size Field Description ------ ---- ------------------- ----------------------------------------------- 0 2 Machine Number identifying type of target machine. 2 2 Number of Sections Number of sections; indicates size of the Section Table, which immediately follows the headers. 4 4 Time/Date Stamp Time and date the file was created. 8 4 Pointer to Symbol Offset, within the COFF file, of the symbol Table table. 12 4 Number of Symbols Number of entries in the symbol table. This data can be used in locating the string table, which immediately follows the symbol table. 16 2 Optional Header Size of the optional header, which is Size included for executable files but not object files. An object file should have a value of 0 here. 18 2 Characteristics Flags indicating attributes of the file. Windows NT Software Development Kit (SDK) provides a utility called DUMPBIN. DUMPBIN is a 32-bit tool that displays information about 32-bit Common Object File Format (COFF) binary files. DUMPBIN runs only from a command prompt. You can use DUMPBIN to examine the following kinds of COFF files: object files, standard libraries of COFF objects, executable files, and dynamic-link library (DLL) files. To run DUMPBIN, use the following syntax: DUMPBIN [options] [files] The following are options parameters and definitions for DUMPBIN: /ALL /ARCHIVEMEMBERS /DISASM /EXPORTS /HEADERS /IMPORTS /LINENUMBERS /LINKERMEMBER[:{1|2}] /OUT:filename /PDATA /RAWDATA[:{NONE|BYTES|SHORTS|LONGS}[,#]] /RELOCATIONS /SECTION:name /SUMMARY /SYMBOLS Options Definition ---------------- ------------------------------------------------------- /ALL Setting this option causes DUMPBIN to display all available information except code disassembly. /ARCHIVEMEMBERS Setting this option causes DUMPBIN to display minimal information about member objects in a library. /DISASM Setting this option causes DUMPBIN to show disassembly of code sections, using symbols if present in the file. /EXPORTS This option causes DUMPBIN to list all definitions exported from an executable file or DLL. /HEADERS Setting this option causes DUMPBIN to display the file header and the header for each section. When used with a library, displays the header for each member object. /IMPORTS This option causes DUMPBIN to list all definitions imported to an executable file or DLL. /LINENUMBERS Setting this option causes DUMPBIN to show COFF line numbers. Line numbers exist in an object file if it was compiled with /Zi. An executable file or DLL contains COFF line numbers if it was linked with /DEBUG and /DEBUGTYPE:COFF option. /LINKERMEMBER [[:{1|2}]] Setting this option causes DUMPBIN to list public symbols defined in a library. Specify the 1 argument to display symbols in object order, along with their offsets. Specify the 2 argument to display offsets and index numbers of objects, then list the symbols in alphabetical order along with the object index for each. To get both outputs, specify /LINKERMEMBER without the number argument. /OUT: This option specifies a filename for the output. /RAWDATA [[:{BYTES|SHORTS|LONGS|NONE}[[,number]]]] Setting this option causes DUMPBIN to display the raw contents of each section in the file. The arguments control the format of the display, as follows: Argument - Result BYTES - The default. Contents are displayed in hexadecimal bytes, and also as ASCII if they have a printed representation. SHORTS - Contents are displayed in hexadecimal words. LONGS - Contents are displayed in hexadecimal longwords. NONE - Raw data is suppressed. This is useful to control the output of /ALL. number - Displayed lines are set to a width that holds number values per line. /RELOCATIONS Setting this option causes DUMPBIN to display any relocations in the object or image. /SECTION:
This option restricts the output to information on the specified section. /SUMMARY Setting this option causes DUMPBIN to display minimal information about sections, including total size. This option is the default if no other option is specified in a DUMPBIN command. /SYMBOLS Setting this option causes DUMPBIN to display the COFF symbol table. Symbol tables exist in all object files. A COFF symbol table appears in an image file only if it is linked with /DEBUG /DEBUGTYPE:COFF Additional query words: prodnt 3.10 entry NTS NTW ====================================================================== Keywords : kbOSWinNT310 kbOSWinNT351 Technology : kbWinNTsearch kbWinNTWsearch kbWinNT350search kbWinNTW350 kbWinNTW350search kbWinNTW310 kbWinNTSsearch kbWinNTS350 kbWinNTS310 kbWinNTAdvSerSearch kbWinNTS350search kbWinNTS310search kbWinNT310Search kbWinNTW310Search Version : :; winnt:3.5 ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2001.