view content of .obj file generated by MSVC compiler ?
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@jsulm : if i have a static variable in my code, can i see those entry in object file ?
@Vinoth-Rajendran4 said in view content of .obj file generated by MSVC compiler ?:
can i see those entry in object file ?
What exactly do you want to see? The value of that variable? And why do you want to see it in object file?
I still fail to understand your use case. -
@Vinoth-Rajendran4 said in view content of .obj file generated by MSVC compiler ?:
can i see those entry in object file ?
What exactly do you want to see? The value of that variable? And why do you want to see it in object file?
I still fail to understand your use case.wrote on 15 Feb 2022, 12:15 last edited by@jsulm : I would like to know the value of the static variable , and where these variable will be placed in memory layout.
I was asked this question in an interview. So I would like to know about it. -
@jsulm : I would like to know the value of the static variable , and where these variable will be placed in memory layout.
I was asked this question in an interview. So I would like to know about it. -
wrote on 15 Feb 2022, 12:58 last edited by
@jsulm : memory layout, i am aware.
But like to know, if we could see the value of static variable in object file ? -
@jsulm : memory layout, i am aware.
But like to know, if we could see the value of static variable in object file ?@Vinoth-Rajendran4 said in view content of .obj file generated by MSVC compiler ?:
if we could see the value of static variable in object file ?
Of couse you can - use a hex editor.
See "4. Let us initialize the static variable which will then be stored in the Data Segment (DS)" in the link I provided. -
wrote on 17 Feb 2022, 21:16 last edited by
NM(1) GNU Development Tools NM(1) NAME nm - list symbols from object files SYNOPSIS nm [-A|-o|--print-file-name] [-a|--debug-syms] [-B|--format=bsd] [-C|--demangle[=style]] [-D|--dynamic] [-fformat|--format=format] [-g|--extern-only] [-h|--help] [-l|--line-numbers] [--inlines] [-n|-v|--numeric-sort] [-P|--portability] [-p|--no-sort] [-r|--reverse-sort] [-S|--print-size] [-s|--print-armap] [-t radix|--radix=radix] [-u|--undefined-only] [-V|--version] [-X 32_64] [--defined-only] [--no-demangle] [--plugin name] [--no-recurse-limit|--recurse-limit]] [--size-sort] [--special-syms] [--synthetic] [--with-symbol-versions] [--target=bfdname] [objfile...] DESCRIPTION GNU nm lists the symbols from object files objfile.... If no object files are listed as arguments, nm assumes the file a.out. For each symbol, nm shows: · The symbol value, in the radix selected by options (see below), or hexadecimal by default. · The symbol type. At least the following types are used; others are, as well, depending on the object file format. If lowercase, the symbol is usually local; if uppercase, the symbol is global (external). There are however a few lowercase symbols that are shown for special global symbols ("u", "v" and "w"). "A" The symbol's value is absolute, and will not be changed by further linking. "B" "b" The symbol is in the BSS data section. This section typically contains zero-initialized or uninitialized data, although the exact behavior is system dependent. "C" The symbol is common. Common symbols are uninitialized data. When linking, multiple common symbols may appear with the same name. If the symbol is defined anywhere, the common symbols are treated as undefined references. "D" "d" The symbol is in the initialized data section. "G" "g" The symbol is in an initialized data section for small objects. Some object file formats permit more efficient access to small data objects, such as a global int variable as opposed to a large global array. "i" For PE format files this indicates that the symbol is in a section specific to the implementation of DLLs. For ELF format files this indicates that the symbol is an indirect function. This is a GNU extension to the standard set of ELF symbol types. It indicates a symbol which if referenced by a relocation does not evaluate to its address, but instead must be invoked at runtime. The runtime execution will then return the value to be used in the relocation. "I" The symbol is an indirect reference to another symbol. "N" The symbol is a debugging symbol. "p" The symbols is in a stack unwind section. "R" "r" The symbol is in a read only data section. "S" "s" The symbol is in an uninitialized or zero-initialized data section for small objects. -
NM(1) GNU Development Tools NM(1) NAME nm - list symbols from object files SYNOPSIS nm [-A|-o|--print-file-name] [-a|--debug-syms] [-B|--format=bsd] [-C|--demangle[=style]] [-D|--dynamic] [-fformat|--format=format] [-g|--extern-only] [-h|--help] [-l|--line-numbers] [--inlines] [-n|-v|--numeric-sort] [-P|--portability] [-p|--no-sort] [-r|--reverse-sort] [-S|--print-size] [-s|--print-armap] [-t radix|--radix=radix] [-u|--undefined-only] [-V|--version] [-X 32_64] [--defined-only] [--no-demangle] [--plugin name] [--no-recurse-limit|--recurse-limit]] [--size-sort] [--special-syms] [--synthetic] [--with-symbol-versions] [--target=bfdname] [objfile...] DESCRIPTION GNU nm lists the symbols from object files objfile.... If no object files are listed as arguments, nm assumes the file a.out. For each symbol, nm shows: · The symbol value, in the radix selected by options (see below), or hexadecimal by default. · The symbol type. At least the following types are used; others are, as well, depending on the object file format. If lowercase, the symbol is usually local; if uppercase, the symbol is global (external). There are however a few lowercase symbols that are shown for special global symbols ("u", "v" and "w"). "A" The symbol's value is absolute, and will not be changed by further linking. "B" "b" The symbol is in the BSS data section. This section typically contains zero-initialized or uninitialized data, although the exact behavior is system dependent. "C" The symbol is common. Common symbols are uninitialized data. When linking, multiple common symbols may appear with the same name. If the symbol is defined anywhere, the common symbols are treated as undefined references. "D" "d" The symbol is in the initialized data section. "G" "g" The symbol is in an initialized data section for small objects. Some object file formats permit more efficient access to small data objects, such as a global int variable as opposed to a large global array. "i" For PE format files this indicates that the symbol is in a section specific to the implementation of DLLs. For ELF format files this indicates that the symbol is an indirect function. This is a GNU extension to the standard set of ELF symbol types. It indicates a symbol which if referenced by a relocation does not evaluate to its address, but instead must be invoked at runtime. The runtime execution will then return the value to be used in the relocation. "I" The symbol is an indirect reference to another symbol. "N" The symbol is a debugging symbol. "p" The symbols is in a stack unwind section. "R" "r" The symbol is in a read only data section. "S" "s" The symbol is in an uninitialized or zero-initialized data section for small objects.wrote on 17 Feb 2022, 21:53 last edited by JonB@Kent-Dorfman
The OP asks about.objfiles from MSVC. You sure UNIX/GNUnmis available and works on these? -
@Kent-Dorfman
The OP asks about.objfiles from MSVC. You sure UNIX/GNUnmis available and works on these?wrote on 17 Feb 2022, 23:42 last edited by@JonB if the object formt is COFF then it will work, even if OP has to build the utility themself. online info suggests that .obj format in windows is in fact COFF.
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@JonB if the object formt is COFF then it will work, even if OP has to build the utility themself. online info suggests that .obj format in windows is in fact COFF.
wrote on 18 Feb 2022, 09:45 last edited by@Kent-Dorfman
I see, if you say so. Still not sure that OP would have a GNUnmutility available. FWIW, What COFF (windows .obj object file) viewers are available? for example statesI am only aware of 2:
dumpbin which is included with Visual Studio
PEView from http://wjradburn.com/software/
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wrote on 18 Feb 2022, 18:52 last edited by Kent-Dorfman
@JonB said in view content of .obj file generated by MSVC compiler ?:
Still not sure that OP would have a GNU nm utility available.
mingw provides the whole slew of gnu utilities as windows native executables. nm should be available, at which point the mingw exe can be used to process the windows native object file.
With a caveat that most folks would probably overlook: OP wants to process C++ object files, in which case the symbol names will probably be name-mangled, unless they were declared as extern "C" {}
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@JonB said in view content of .obj file generated by MSVC compiler ?:
Still not sure that OP would have a GNU nm utility available.
mingw provides the whole slew of gnu utilities as windows native executables. nm should be available, at which point the mingw exe can be used to process the windows native object file.
With a caveat that most folks would probably overlook: OP wants to process C++ object files, in which case the symbol names will probably be name-mangled, unless they were declared as extern "C" {}
wrote on 18 Feb 2022, 19:20 last edited by JonB@Kent-Dorfman said in view content of .obj file generated by MSVC compiler ?:
mingw provides the whole slew of gnu utilities as windows native executables. nm should be available,
Ooohhh, sorry, right, that makes sense!
Though I thought MinGW did
.onot.objfiles, I thought that meant MSVC. But what do I know?! :) -
You don't need any unix or otherwise external tools. MSVC installation already comes with the dumpbin utility that lets you see various information about the structure and contents of COFF files. It also undecorates C++ function names, so no problem there either.
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You don't need any unix or otherwise external tools. MSVC installation already comes with the dumpbin utility that lets you see various information about the structure and contents of COFF files. It also undecorates C++ function names, so no problem there either.
wrote on 20 Feb 2022, 08:57 last edited by@Chris-Kawa : Thanks for the utility tool suggestion.
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NM(1) GNU Development Tools NM(1) NAME nm - list symbols from object files SYNOPSIS nm [-A|-o|--print-file-name] [-a|--debug-syms] [-B|--format=bsd] [-C|--demangle[=style]] [-D|--dynamic] [-fformat|--format=format] [-g|--extern-only] [-h|--help] [-l|--line-numbers] [--inlines] [-n|-v|--numeric-sort] [-P|--portability] [-p|--no-sort] [-r|--reverse-sort] [-S|--print-size] [-s|--print-armap] [-t radix|--radix=radix] [-u|--undefined-only] [-V|--version] [-X 32_64] [--defined-only] [--no-demangle] [--plugin name] [--no-recurse-limit|--recurse-limit]] [--size-sort] [--special-syms] [--synthetic] [--with-symbol-versions] [--target=bfdname] [objfile...] DESCRIPTION GNU nm lists the symbols from object files objfile.... If no object files are listed as arguments, nm assumes the file a.out. For each symbol, nm shows: · The symbol value, in the radix selected by options (see below), or hexadecimal by default. · The symbol type. At least the following types are used; others are, as well, depending on the object file format. If lowercase, the symbol is usually local; if uppercase, the symbol is global (external). There are however a few lowercase symbols that are shown for special global symbols ("u", "v" and "w"). "A" The symbol's value is absolute, and will not be changed by further linking. "B" "b" The symbol is in the BSS data section. This section typically contains zero-initialized or uninitialized data, although the exact behavior is system dependent. "C" The symbol is common. Common symbols are uninitialized data. When linking, multiple common symbols may appear with the same name. If the symbol is defined anywhere, the common symbols are treated as undefined references. "D" "d" The symbol is in the initialized data section. "G" "g" The symbol is in an initialized data section for small objects. Some object file formats permit more efficient access to small data objects, such as a global int variable as opposed to a large global array. "i" For PE format files this indicates that the symbol is in a section specific to the implementation of DLLs. For ELF format files this indicates that the symbol is an indirect function. This is a GNU extension to the standard set of ELF symbol types. It indicates a symbol which if referenced by a relocation does not evaluate to its address, but instead must be invoked at runtime. The runtime execution will then return the value to be used in the relocation. "I" The symbol is an indirect reference to another symbol. "N" The symbol is a debugging symbol. "p" The symbols is in a stack unwind section. "R" "r" The symbol is in a read only data section. "S" "s" The symbol is in an uninitialized or zero-initialized data section for small objects.wrote on 20 Feb 2022, 08:58 last edited by@Kent-Dorfman : Thanks for suggesting nm utility.
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@Kent-Dorfman
I see, if you say so. Still not sure that OP would have a GNUnmutility available. FWIW, What COFF (windows .obj object file) viewers are available? for example statesI am only aware of 2:
dumpbin which is included with Visual Studio
PEView from http://wjradburn.com/software/
wrote on 20 Feb 2022, 09:54 last edited by JonB@JonB said in view content of .obj file generated by MSVC compiler ?:
(https://stackoverflow.com/questions/2262959/what-coff-windows-obj-object-file-viewers-are-available) for example states
I am only aware of 2:dumpbin which is included with Visual Studio
PEView from http://wjradburn.com/software/
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