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  .\" $Id: gelf_getsym.3 3734 2019-04-22 14:10:49Z jkoshy $
  .\"
  .Dd April 22, 2019
  .Dt GELF_GETSYM 3
  .Os
  .Sh NAME
  .Nm gelf_getsym ,
  .Nm gelf_update_sym
  .Nd read and update symbol information
  .Sh LIBRARY
  .Lb libelf
  .Sh SYNOPSIS
  .In gelf.h
  .Ft "GElf_Sym *"
  .Fn gelf_getsym "Elf_Data *data" "int ndx" "GElf_Sym *sym"
  .Ft int
  .Fn gelf_update_sym "Elf_Data *data" "int ndx" "GElf_Sym *sym"
  .Sh DESCRIPTION
  These convenience functions are used to retrieve and update class-dependent
  .Vt Elf32_Sym
  and
  .Vt Elf64_Sym
  structures in an ELF object.
  .Pp
  Argument
  .Ar data
  is an
  .Vt Elf_Data
  descriptor associated with a section of type
  .Dv SHT_SYMTAB ,
  .Dv SHT_DYNSYM
  or
  .Dv SHT_GNU_versym .
  Argument
  .Ar ndx
  is the index of the symbol being retrieved or updated.
  The class-independent
  .Vt GElf_Sym
  structure is described in
  .Xr gelf 3 .
  .Pp
  Function
  .Fn gelf_getsym
  retrieves class-dependent symbol information at index
  .Ar ndx
  in data buffer
  .Ar data
  and copies it to the destination pointed to by argument
  .Ar sym
  after translation to class-independent form.
  .Pp
  Function
  .Fn gelf_update_sym
  converts the class-independent symbol information pointed to
  by argument
  .Ar sym
  to class-dependent form, and writes it to the symbol entry at index
  .Ar ndx
  in the data buffer described by argument
  .Ar data .
  Function
  .Fn gelf_update_sym
  signals an error if any of the values in the class-independent
  representation exceeds the representable limits of the target
  type.
  .Sh RETURN VALUES
  Function
  .Fn gelf_getsym
  returns the value of argument
  .Ar sym
  if successful, or NULL in case of an error.
  Function
  .Fn gelf_update_sym
  returns a non-zero value if successful, or zero in case of an error.
  .Sh ERRORS
  These functions may fail with the following errors:
  .Bl -tag -width "[ELF_E_RESOURCE]"
  .It Bq Er ELF_E_ARGUMENT
  Arguments
  .Ar data
  or
  .Ar sym
  were NULL.
  .It Bq Er ELF_E_ARGUMENT
  Argument
  .Ar ndx
  was less than zero or larger than the number of symbols in the data
  descriptor.
  .It Bq Er ELF_E_ARGUMENT
  Data descriptor
  .Ar data
  was not associated with a section containing symbol information.
  .It Bq Er ELF_E_RANGE
  A value was not representable in the target type.
  .It Bq Er ELF_E_VERSION
  The
  .Vt Elf_Data
  descriptor denoted by argument
  .Ar data
  is associated with an ELF object with an unsupported version.
  .El
  .Sh SEE ALSO
  .Xr elf 3 ,
  .Xr elf_getdata 3 ,
  .Xr elf_getscn 3 ,
  .Xr gelf 3 ,
  .Xr gelf_getsyminfo 3 ,
  .Xr gelf_update_syminfo 3
  