GELF_GETNOTE(3)           Libelf Programmer's Manual           GELF_GETNOTE(3)



NAME
       gelf_getnote - Get class-independent note information at the supplied
       offset


SYNOPSIS
       #include <gelf.h>

       size_t gelf_getnote (Elf_Data *data, size_t offset, GElf_Nhdr *result, size_t *name_offset, size_t *desc_offset);


DESCRIPTION
       Retrieve the ELF note header from data at offset offset and store it in
       a class-independent representation pointed to by result.  The note name
       and note descriptor offsets relative to the start of data are stored in
       *name_offset and *desc_offset, respectively.  GElf_Nhdr fields
       n_namesz, n_descsz, and n_type describe the note's name length,
       descriptor length and type, respectively.  Alignment and padding of the
       note data entry are handled automatically by this function.  See elf(5)
       for more information regarding ELF notes.


PARAMETERS
       data   Pointer to an Elf_Data associated with a SHT_NOTE section or a
              PT_NOTE segment.  data->d_type should be ELF_T_NHDR or
              ELF_T_NHDR8.


       offset Offset of a note header within data.


       result Pointer to a caller-provided GElf_Nhdr structure for storing the
              requested note header.  result must not be NULL.


       name_offset
              Pointer to a caller-provided size_t for storing the name offset
              of the requested note.  This offset is relative to data->d_buf.
              name_offset must not be NULL.


       desc_offset
              Pointer to a caller-provided size_t for storing the descriptor
              offset of the requested note. This offset is relative to
              data->d_buf.  desc_offset must not be NULL.


RETURN VALUE
       On success, this function updates *result, *name_offset, and
       *desc_offset and returns the offset of the next note.  If there are no
       notes remaining then the return value will be greater than or equal to
       the d_size of data.  On failure, this function returns zero and sets
       elf_errno.  If data is NULL then zero is returned without setting
       elf_errno.


EXAMPLE
         size_t offset = 0;
         GElf_Nhdr nhdr;
         size_t name_offset;
         size_t desc_offset;
         while (offset < data->d_size
                && (offset = gelf_getnote (data, offset,
                                           &nhdr, &name_offset, &desc_offset)) > 0)
           {
             const char *name = nhdr.n_namesz == 0 ? "" : data->d_buf + name_offset;
             const char *desc = nhdr.n_descsz == 0 ? "" : data->d_buf + desc_offset;

             /* Process note here.  name and desc are not guaranteed to be
                zero-terminated.  The presence of null characters should be
                verified using n_namesz and n_descsz.  */
             [...]
           }


SEE ALSO
       libelf(3), elf(5)


ATTRIBUTES

       +--------------------------------------------+---------------+---------+
       |Interface                                   | Attribute     | Value   |
       +--------------------------------------------+---------------+---------+
       |gelf_getnote ()                             | Thread safety | MT-Safe |
       +--------------------------------------------+---------------+---------+

REPORTING BUGS
       Report bugs to <elfutils-devel@sourceware.org> or
       https://sourceware.org/bugzilla/.


HISTORY
       gelf_getnote first appeared in elfutils 0.130.  This function is an
       elfutils libelf extension and may not be available in other libelf
       implementations.

Libelf                            2025-12-31                   GELF_GETNOTE(3)