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24.\" $Id: gelf_checksum.3 3639 2018-10-14 14:07:02Z jkoshy $
25.\"
26.Dd August 29, 2006
27.Dt GELF_CHECKSUM 3
28.Os
29.Sh NAME
30.Nm elf32_checksum ,
31.Nm elf64_checksum ,
32.Nm gelf_checksum
33.Nd return the checksum of an ELF object
34.Sh LIBRARY
35.Lb libelf
36.Sh SYNOPSIS
37.In libelf.h
38.Ft long
39.Fn elf32_checksum "Elf *elf"
40.Ft long
41.Fn elf64_checksum "Elf *elf"
42.In gelf.h
43.Ft long
44.Fn gelf_checksum "Elf *elf"
45.Sh DESCRIPTION
46These functions return a simple checksum of the ELF object described
47by their argument
48.Ar elf .
49The checksum is computed in way that allows its value to remain
50unchanged in presence of modifications to the ELF object by utilities
51like
52.Xr strip 1 .
53.Pp
54Function
55.Fn elf32_checksum
56returns a checksum for an ELF descriptor
57.Ar elf
58of class
59.Dv ELFCLASS32 .
60.Pp
61Function
62.Fn elf64_checksum
63returns a checksum for an ELF descriptor
64.Ar elf
65of class
66.Dv ELFCLASS64 .
67.Pp
68Function
69.Fn gelf_checksum
70provides a class-independent way retrieving the checksum
71for ELF object
72.Ar elf .
73.Sh RETURN VALUES
74These functions return the checksum of the ELF object, or zero in case
75an error was encountered.
76.Sh ERRORS
77These functions may fail with the following errors:
78.Bl -tag -width "[ELF_E_RESOURCE]"
79.It Bq Er ELF_E_ARGUMENT
80Argument
81.Ar elf
82was NULL.
83.It Bq Er ELF_E_ARGUMENT
84Argument
85.Ar elf
86was not a descriptor for an ELF file.
87.It Bq Er ELF_E_ARGUMENT
88The ELF descriptor
89.Ar elf
90was not opened for reading or updating.
91.It Bq Er ELF_E_CLASS
92For functions
93.Fn elf32_checksum
94and
95.Fn elf64_checksum ,
96ELF descriptor
97.Ar elf
98did not match the class of the called function.
99.It Bq Er ELF_E_HEADER
100The ELF object specified by argument
101.Ar elf
102had a malformed executable header.
103.It Bq Er ELF_E_RESOURCE
104An out of memory condition was detected during processing.
105.It Bq Er ELF_E_SECTION
106The ELF object specified by argument
107.Ar elf
108contained a section with a malformed section header.
109.It Bq Er ELF_E_VERSION
110The ELF object was of an unsupported version.
111.El
112.Sh SEE ALSO
113.Xr strip 1 ,
114.Xr elf 3 ,
115.Xr gelf 3
116