NAME
objcopy - copy and translate object files
SYNOPSIS
objcopy [-F bfdnameï target=bfdname]
[-I bfdnameï inputtarget=bfdname]
[-O bfdnameï outputtarget=bfdname]
[-Sï stripall] [-gï stripdebug]
[-K symbolnameï keepsymbol=symbolname]
[-N symbolnameï stripsymbol=symbolname]
[-G symbolnameï keepglobalsymbol=symbolname]
[-L symbolnameï localizesymbol=symbolname]
[-W symbolnameï weakensymbol=symbolname]
[-xï discardall] [-Xï discardlocals]
[-b byteï byte=byte]
[-i interleaveï interleave=interleave]
[-j sectionnameï onlysection=sectionname]
[-R sectionnameï removesection=sectionname]
[-pï preservedates] [ debugging]
[ gapfill=val] [ padto=address]
[ setstart=val] [ adjuststart=incr]
[ changeaddresses=incr]
[ changesectionaddress section{=,+,-}val]
[ changesectionlma section{=,+,-}val]
[ changesectionvma section{=,+,-}val]
[ changewarnings] [ nochangewarnings]
[ setsectionflags section=flags]
[ addsection sectionname=filename]
[ changeleadingchar] [ removeleadingchar]
[ sreclen=ival ] [ srecforceS3]
[ redefinesym old=new ] [ weaken]
[ keepsymbols=filename]
[ stripsymbols=filename]
[ keepglobalsymbols=filename]
[ localizesymbols=filename]
[ weakensymbols=filename]
[-vï verbose] [-Vï version] [ help]
infile [outfile]
DESCRIPTION
The GNU objcopy utility copies the contents of an object file to another. objcopy uses the
GNU BFD Library to read and write the object files. It can write the destination object file in a
format different from that of the source object file. The exact behavior of objcopy is
controlled by commandline options. Note that objcopy should be able to copy a fully linked
file between any two formats. However, copying a relocatable object file between any two
formats may not work as expected.
objcopy creates temporary files to do its translations and deletes them afterward. objcopy
uses BFD to do all its translation work; it has access to all the formats described in BFD and
thus is able to recognize most formats without being told explicitly.
objcopy can be used to generate Srecords by using an output target of srec (e.g., use -O
srec).
objcopy can be used to generate a raw binary file by using an output target of binary (e.g.,
use -O binary). When objcopy generates a raw binary file, it will essentially produce a
memory dump of the contents of the input object file. All symbols and relocation information
will be discarded. The memory dump will start at the load address of the lowest section
copied into the output file.
When generating an Srecord or a raw binary file, it may be helpful to use -S to remove
sections containing debugging information. In some cases -R will be useful to remove
sections which contain information that is not needed by the binary file.
Note - objcopy is not able to change the endianness of its input files. If the input format has
an endianness, (some formats do not), objcopy can only copy the inputs into file formats that
have the same endianness or which have no endianness (eg srec).
OPTIONS
infile
outfile
The input and output files, respectively. If you do not specify outfile, objcopy creates a
temporary file and destructively renames the result with the name of infile.
-I bfdname
inputtarget=bfdname
Consider the source file's object format to be bfdname, rather than attempting to deduce
it.
-O bfdname
outputtarget=bfdname
Write the output file using the object format bfdname.
-F bfdname
target=bfdname
Use bfdname as the object format for both the input and the output file; i.e., simply
transfer data from source to destination with no translation.
-j sectionname
onlysection=sectionname
Copy only the named section from the input file to the output file. This option may be
given more than once. Note that using this option inappropriately may make the output
file unusable.
-R sectionname
removesection=sectionname
Remove any section named sectionname from the output file. This option may be given
more than once. Note that using this option inappropriately may make the output file
unusable.
-S
stripall
Do not copy relocation and symbol information from the source file.
-g
stripdebug
Do not copy debugging symbols from the source file.
stripunneeded
Strip all symbols that are not needed for relocation processing.
-K symbolname
keepsymbol=symbolname
Copy only symbol symbolname from the source file. This option may be given more than
once.
-N symbolname
stripsymbol=symbolname
Do not copy symbol symbolname from the source file. This option may be given more
than once.
-G symbolname
keepglobalsymbol=symbolname
Keep only symbol symbolname global. Make all other symbols local to the file, so that
they are not visible externally. This option may be given more than once.
-L symbolname
localizesymbol=symbolname
Make symbol symbolname local to the file, so that it is not visible externally. This option
may be given more than once.
-W symbolname
weakensymbol=symbolname
Make symbol symbolname weak. This option may be given more than once.
-x
discardall
Do not copy nonglobal symbols from the source file.
-X
discardlocals
Do not copy compilergenerated local symbols. (These usually start with L or ..)
-b byte
byte=byte
Keep only every byteth byte of the input file (header data is not affected). byte can be in
the range from 0 to interleave-1, where interleave is given by the -i or interleave
option, or the default of 4. This option is useful for creating files to program ROM. It is
typically used with an srec output target.
-i interleave
interleave=interleave
Only copy one out of every interleave bytes. Select which byte to copy with the -b or
byte option. The default is 4. objcopy ignores this option if you do not specify either
-b or byte.
-p
preservedates
Set the access and modification dates of the output file to be the same as those of the
input file.
debugging
Convert debugging information, if possible. This is not the default because only certain
debugging formats are supported, and the conversion process can be time consuming.
gapfill val
Fill gaps between sections with val. This operation applies to the load address (LMA) of
the sections. It is done by increasing the size of the section with the lower address, and
filling in the extra space created with val.
padto address
Pad the output file up to the load address address. This is done by increasing the size of
the last section. The extra space is filled in with the value specified by gapfill (default
zero).
setstart val
Set the start address of the new file to val. Not all object file formats support setting the
start address.
changestart incr
adjuststart incr
Change the start address by adding incr. Not all object file formats support setting the
start address.
changeaddresses incr
adjustvma incr
Change the VMA and LMA addresses of all sections, as well as the start address, by
adding incr. Some object file formats do not permit section addresses to be changed
arbitrarily. Note that this does not relocate the sections; if the program expects sections
to be loaded at a certain address, and this option is used to change the sections such that
they are loaded at a different address, the program may fail.
changesectionaddress section{=,+,-}val
adjustsectionvma section{=,+,-}val
Set or change both the VMA address and the LMA address of the named section. If = is
used, the section address is set to val. Otherwise, val is added to or subtracted from the
section address. See the comments under changeaddresses, above. If section does
not exist in the input file, a warning will be issued, unless nochangewarnings is used.
changesectionlma section{=,+,-}val
Set or change the LMA address of the named section. The LMA address is the address
where the section will be loaded into memory at program load time. Normally this is the
same as the VMA address, which is the address of the section at program run time, but on
some systems, especially those where a program is held in ROM, the two can be
different. If = is used, the section address is set to val. Otherwise, val is added to or
subtracted from the section address. See the comments under changeaddresses,
above. If section does not exist in the input file, a warning will be issued, unless
nochangewarnings is used.
changesectionvma section{=,+,-}val
Set or change the VMA address of the named section. The VMA address is the address
where the section will be located once the program has started executing. Normally this
is the same as the LMA address, which is the address where the section will be loaded
into memory, but on some systems, especially those where a program is held in ROM, the
two can be different. If = is used, the section address is set to val. Otherwise, val is
added to or subtracted from the section address. See the comments under
changeaddresses, above. If section does not exist in the input file, a warning will be
issued, unless nochangewarnings is used.
changewarnings
adjustwarnings
If changesectionaddress or changesectionlma or changesectionvma is used,
and the named section does not exist, issue a warning. This is the default.
nochangewarnings
noadjustwarnings
Do not issue a warning if changesectionaddress or adjustsectionlma or
adjustsectionvma is used, even if the named section does not exist.
setsectionflags section=flags
Set the flags for the named section. The flags argument is a comma separated string of
flag names. The recognized names are alloc, contents, load, noload, readonly, code,
data, rom, share, and debug. You can set the contents flag for a section which does not
have contents, but it is not meaningful to clear the contents flag of a section which does
have contentsjust remove the section instead. Not all flags are meaningful for all
object file formats.
addsection sectionname=filename
Add a new section named sectionname while copying the file. The contents of the new
section are taken from the file filename. The size of the section will be the size of the file.
This option only works on file formats which can support sections with arbitrary names.
changeleadingchar
Some object file formats use special characters at the start of symbols. The most
common such character is underscore, which compilers often add before every symbol.
This option tells objcopy to change the leading character of every symbol when it
converts between object file formats. If the object file formats use the same leading
character, this option has no effect. Otherwise, it will add a character, or remove a
character, or change a character, as appropriate.
removeleadingchar
If the first character of a global symbol is a special symbol leading character used by the
object file format, remove the character. The most common symbol leading character is
underscore. This option will remove a leading underscore from all global symbols. This
can be useful if you want to link together objects of different file formats with different
conventions for symbol names. This is different from changeleadingchar because it
always changes the symbol name when appropriate, regardless of the object file format
of the output file.
sreclen=ival
Meaningful only for srec output. Set the maximum length of the Srecords being
produced to ival. This length covers both address, data and crc fields.
srecforceS3
Meaningful only for srec output. Avoid generation of S1/S2 records, creating S3-only
record format.
redefinesym old=new
Change the name of a symbol old, to new. This can be useful when one is trying link two
things together for which you have no source, and there are name collisions.
weaken
Change all global symbols in the file to be weak. This can be useful when building an
object which will be linked against other objects using the -R option to the linker. This
option is only effective when using an object file format which supports weak symbols.
keepsymbols=filename
Apply keepsymbol option to each symbol listed in the file filename. filename is
simply a flat file, with one symbol name per line. Line comments may be introduced by
the hash character. This option may be given more than once.
stripsymbols=filename
Apply stripsymbol option to each symbol listed in the file filename. filename is
simply a flat file, with one symbol name per line. Line comments may be introduced by
the hash character. This option may be given more than once.
keepglobalsymbols=filename
Apply keepglobalsymbol option to each symbol listed in the file filename. filename
is simply a flat file, with one symbol name per line. Line comments may be introduced by
the hash character. This option may be given more than once.
localizesymbols=filename
Apply localizesymbol option to each symbol listed in the file filename. filename is
simply a flat file, with one symbol name per line. Line comments may be introduced by
the hash character. This option may be given more than once.
weakensymbols=filename
Apply weakensymbol option to each symbol listed in the file filename. filename is
simply a flat file, with one symbol name per line. Line comments may be introduced by
the hash character. This option may be given more than once.
-V
version
Show the version number of objcopy.
-v
verbose
Verbose output: list all object files modified. In the case of archives, objcopy -V lists all
members of the archive.
help
Show a summary of the options to objcopy.
SEE ALSO
ld (1), objdump (1), and the Info entries for binutils.
COPYRIGHT
Copyright (c) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document under the terms of the
GNU Free Documentation License, Version 1.1 or any later version published by the Free
Software Foundation; with no Invariant Sections, with no FrontCover Texts, and with no
BackCover Texts. A copy of the license is included in the section entitled ``GNU Free
Documentation License''.