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 24  .\" $Id$
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 26  .Dd August 29, 2006
 27  .Os
 28  .Dt GELF_GETRELA 3
 29  .Sh NAME
 30  .Nm gelf_getrela ,
 31  .Nm gelf_update_rela
 32  .Nd read and update ELF relocation entries with addends
 33  .Sh LIBRARY
 34  .Lb libelf
 35  .Sh SYNOPSIS
 36  .In gelf.h
 37  .Ft "GElf_Rela *"
 38  .Fn gelf_getrela "Elf_Data *data" "int ndx" "GElf_Rela *rela"
 39  .Ft int
 40  .Fn gelf_update_rela "Elf_Data *data" "int ndx" "GElf_Rela *rela"
 41  .Sh DESCRIPTION
 42  These convenience functions are used to retrieve and update class-dependent
 43  .Vt Elf32_Rela
 44  or
 45  .Vt Elf64_Rela
 46  structures in an ELF object.
 47  .Pp
 48  Argument
 49  .Ar data
 50  is an
 51  .Vt Elf_Data
 52  descriptor associated with a section of type
 53  .Dv SHT_RELA .
 54  Argument
 55  .Ar ndx
 56  is the index of the entry being retrieved or updated.
 57  The class-independent
 58  .Vt GElf_Rela
 59  structure is described in
 60  .Xr gelf 3 .
 61  .Pp
 62  Function
 63  .Fn gelf_getrela
 64  retrieves the class-dependent entry at index
 65  .Ar ndx
 66  in data buffer
 67  .Ar data
 68  and copies it to the destination pointed to by argument
 69  .Ar rela
 70  after translation to class-independent form.
 71  .Pp
 72  Function
 73  .Fn gelf_update_rela
 74  converts the class-independent entry pointed to
 75  by argument
 76  .Ar rela
 77  to class-dependent form, and writes it to the entry at index
 78  .Ar ndx
 79  in the data buffer described by argument
 80  .Ar data .
 81  Function
 82  .Fn gelf_update_rela
 83  signals an error if any of the values in the class-independent
 84  representation exceeds the representable limits of the target
 85  type.
 86  .Sh RETURN VALUES
 87  Function
 88  .Fn gelf_getrela
 89  returns the value of argument
 90  .Ar rela
 91  if successful, or NULL in case of an error.
 92  Function
 93  .Fn gelf_update_rela
 94  returns a non-zero value if successful, or zero in case of an error.
 95  .Sh ERRORS
 96  These functions may fail with the following errors:
 97  .Bl -tag -width "[ELF_E_RESOURCE]"
 98  .It Bq Er ELF_E_ARGUMENT
 99  Arguments
100  .Ar data
101  or
102  .Ar rela
103  were NULL.
104  .It Bq Er ELF_E_ARGUMENT
105  Argument
106  .Ar ndx
107  was less than zero or larger than the number of entries in the data
108  descriptor.
109  .It Bq Er ELF_E_ARGUMENT
110  Data descriptor
111  .Ar data
112  was not associated with a section of type
113  .Dv SHT_RELA .
114  .It Bq Er ELF_E_RANGE
115  A value was not representable in the target type.
116  .El
117  .Sh SEE ALSO
118  .Xr elf 3 ,
119  .Xr elf_getdata 3 ,
120  .Xr elf_getscn 3 ,
121  .Xr gelf 3