IMAGE_SECTION_HEADER structure

Represents the image section header format.

Syntax

typedef struct _IMAGE_SECTION_HEADER {
  BYTE  Name[IMAGE_SIZEOF_SHORT_NAME];
  union {
    DWORD PhysicalAddress;
    DWORD VirtualSize;
  } Misc;
  DWORD VirtualAddress;
  DWORD SizeOfRawData;
  DWORD PointerToRawData;
  DWORD PointerToRelocations;
  DWORD PointerToLinenumbers;
  WORD  NumberOfRelocations;
  WORD  NumberOfLinenumbers;
  DWORD Characteristics;
} IMAGE_SECTION_HEADER, *PIMAGE_SECTION_HEADER;

Members

Name

An 8-byte, null-padded UTF-8 string. There is no terminating null character if the string is exactly eight characters long. For longer names, this member contains a forward slash (/) followed by an ASCII representation of a decimal number that is an offset into the string table. Executable images do not use a string table and do not support section names longer than eight characters.

Misc

PhysicalAddress

The file address.

VirtualSize

The total size of the section when loaded into memory, in bytes. If this value is greater than the SizeOfRawData member, the section is filled with zeroes. This field is valid only for executable images and should be set to 0 for object files.

VirtualAddress

The address of the first byte of the section when loaded into memory, relative to the image base. For object files, this is the address of the first byte before relocation is applied.

SizeOfRawData

The size of the initialized data on disk, in bytes. This value must be a multiple of the FileAlignment member of the IMAGE_OPTIONAL_HEADER structure. If this value is less than the VirtualSize member, the remainder of the section is filled with zeroes. If the section contains only uninitialized data, the member is zero.

PointerToRawData

A file pointer to the first page within the COFF file. This value must be a multiple of the FileAlignment member of the IMAGE_OPTIONAL_HEADER structure. If a section contains only uninitialized data, set this member is zero.

PointerToRelocations

A file pointer to the beginning of the relocation entries for the section. If there are no relocations, this value is zero.

PointerToLinenumbers

A file pointer to the beginning of the line-number entries for the section. If there are no COFF line numbers, this value is zero.

NumberOfRelocations

The number of relocation entries for the section. This value is zero for executable images.

NumberOfLinenumbers

The number of line-number entries for the section.

Characteristics

The characteristics of the image. The following values are defined.

Flag	Meaning
0x00000000	Reserved.
0x00000001	Reserved.
0x00000002	Reserved.
0x00000004	Reserved.
IMAGE_SCN_TYPE_NO_PAD 0x00000008	The section should not be padded to the next boundary. This flag is obsolete and is replaced by IMAGE_SCN_ALIGN_1BYTES.
0x00000010	Reserved.
IMAGE_SCN_CNT_CODE 0x00000020	The section contains executable code.
IMAGE_SCN_CNT_INITIALIZED_DATA 0x00000040	The section contains initialized data.
IMAGE_SCN_CNT_UNINITIALIZED_DATA 0x00000080	The section contains uninitialized data.
IMAGE_SCN_LNK_OTHER 0x00000100	Reserved.
IMAGE_SCN_LNK_INFO 0x00000200	The section contains comments or other information. This is valid only for object files.
0x00000400	Reserved.
IMAGE_SCN_LNK_REMOVE 0x00000800	The section will not become part of the image. This is valid only for object files.
IMAGE_SCN_LNK_COMDAT 0x00001000	The section contains COMDAT data. This is valid only for object files.
0x00002000	Reserved.
IMAGE_SCN_NO_DEFER_SPEC_EXC 0x00004000	Reset speculative exceptions handling bits in the TLB entries for this section.
IMAGE_SCN_GPREL 0x00008000	The section contains data referenced through the global pointer.
0x00010000	Reserved.
IMAGE_SCN_MEM_PURGEABLE 0x00020000	Reserved.
IMAGE_SCN_MEM_LOCKED 0x00040000	Reserved.
IMAGE_SCN_MEM_PRELOAD 0x00080000	Reserved.
IMAGE_SCN_ALIGN_1BYTES 0x00100000	Align data on a 1-byte boundary. This is valid only for object files.
IMAGE_SCN_ALIGN_2BYTES 0x00200000	Align data on a 2-byte boundary. This is valid only for object files.
IMAGE_SCN_ALIGN_4BYTES 0x00300000	Align data on a 4-byte boundary. This is valid only for object files.
IMAGE_SCN_ALIGN_8BYTES 0x00400000	Align data on a 8-byte boundary. This is valid only for object files.
IMAGE_SCN_ALIGN_16BYTES 0x00500000	Align data on a 16-byte boundary. This is valid only for object files.
IMAGE_SCN_ALIGN_32BYTES 0x00600000	Align data on a 32-byte boundary. This is valid only for object files.
IMAGE_SCN_ALIGN_64BYTES 0x00700000	Align data on a 64-byte boundary. This is valid only for object files.
IMAGE_SCN_ALIGN_128BYTES 0x00800000	Align data on a 128-byte boundary. This is valid only for object files.
IMAGE_SCN_ALIGN_256BYTES 0x00900000	Align data on a 256-byte boundary. This is valid only for object files.
IMAGE_SCN_ALIGN_512BYTES 0x00A00000	Align data on a 512-byte boundary. This is valid only for object files.
IMAGE_SCN_ALIGN_1024BYTES 0x00B00000	Align data on a 1024-byte boundary. This is valid only for object files.
IMAGE_SCN_ALIGN_2048BYTES 0x00C00000	Align data on a 2048-byte boundary. This is valid only for object files.
IMAGE_SCN_ALIGN_4096BYTES 0x00D00000	Align data on a 4096-byte boundary. This is valid only for object files.
IMAGE_SCN_ALIGN_8192BYTES 0x00E00000	Align data on a 8192-byte boundary. This is valid only for object files.
IMAGE_SCN_LNK_NRELOC_OVFL 0x01000000	The section contains extended relocations. The count of relocations for the section exceeds the 16 bits that is reserved for it in the section header. If the NumberOfRelocations field in the section header is 0xffff, the actual relocation count is stored in the VirtualAddress field of the first relocation. It is an error if IMAGE_SCN_LNK_NRELOC_OVFL is set and there are fewer than 0xffff relocations in the section.
IMAGE_SCN_MEM_DISCARDABLE 0x02000000	The section can be discarded as needed.
IMAGE_SCN_MEM_NOT_CACHED 0x04000000	The section cannot be cached.
IMAGE_SCN_MEM_NOT_PAGED 0x08000000	The section cannot be paged.
IMAGE_SCN_MEM_SHARED 0x10000000	The section can be shared in memory.
IMAGE_SCN_MEM_EXECUTE 0x20000000	The section can be executed as code.
IMAGE_SCN_MEM_READ 0x40000000	The section can be read.
IMAGE_SCN_MEM_WRITE 0x80000000	The section can be written to.

 

Requirements

See also

ImageHlp Structures

ImageDirectoryEntryToDataEx

ImageRvaToSection

ImageRvaToVa

LOADED_IMAGE