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24  .\" $Id$
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26  .Dd November 9, 2011
27  .Os
28  .Dt ELF_VERSION 3
29  .Sh NAME
30  .Nm elf_version
31  .Nd retrieve or set ELF library operating version
32  .Sh LIBRARY
33  .Lb libelf
34  .Sh SYNOPSIS
35  .In libelf.h
36  .Ft unsigned int
37  .Fn elf_version "unsigned int version"
38  .Sh DESCRIPTION
39  The
40  .Fn elf_version
41  function is used to query the current operating version of the ELF
42  library, and to inform the ELF library about the application's desired
43  operating version.
44  .Pp
45  If the argument
46  .Ar version
47  is
48  .Dv EV_NONE ,
49  the
50  .Fn elf_version
51  function returns the currently configured operating version for the
52  ELF library.
53  .Pp
54  If the argument
55  .Ar version
56  is not
57  .Dv EV_NONE ,
58  and if argument
59  .Ar version
60  is supported by the ELF library, function
61  .Fn elf_version
62  sets the library's operating version to
63  .Ar version ,
64  and returns the previous value of the operating version.
65  If argument
66  .Ar version
67  cannot be supported, then the
68  .Fn elf_version
69  function returns
70  .Dv EV_NONE .
71  .Sh RETURN VALUES
72  The
73  .Fn elf_version
74  function returns the currently configured ELF library version, or
75  .Dv EV_NONE
76  if an unsupported version is requested.
77  .Sh EXAMPLES
78  An application program would inform the ELF library about its desired
79  operating version and check for an error using the following code
80  snippet:
81  .Bd -literal -offset indent
82  if (elf_version(EV_CURRENT) == EV_NONE)
83  	err(EXIT_FAILURE, "ELF library too old");
84  .Ed
85  .Sh ERRORS
86  Function
87  .Fn elf_version
88  may fail with the following error:
89  .Bl -tag -width "[ELF_E_RESOURCE]"
90  .It Bq Er "ELF_E_VERSION"
91  An unsupported library version number was requested.
92  .El
93  .Sh SEE ALSO
94  .Xr elf 3 ,
95  .Xr gelf 3