dpkg-gensymbols - Linux
Overview
dpkg-gensymbols generates symbol files (.syms) for use in linking shared libraries. It takes a binary file as input and parses its symbol table to create a symbol file. Symbol files contain information about the symbols exported by a library, and are used by linkers to resolve external references.
Syntax
dpkg-gensymbols [options] <binary-file> [<output-file>]
Options/Flags
- -o,
--output=: Specify an output file name. The default is <binary-file>.syms. - -s,
--soname=: Override the SONAME of the binary file. - -l,
--local: Generate a local symbol file, which only contains symbols that are not defined by other shared libraries. - -e,
--exclude=: Exclude symbols matching the regular expression from the symbol file.
Examples
Generate a symbol file for the shared library libfoo.so:
dpkg-gensymbols /usr/lib/libfoo.so
Generate a local symbol file for the binary myprogram:
dpkg-gensymbols -l myprogram
Common Issues
- Missing symbol files: If a shared library does not have a corresponding symbol file, the linker may fail to resolve external references. Always generate symbol files for shared libraries before linking them into other programs.
- Incorrect SONAME: The SONAME of a shared library must match the name specified in its symbol file. If the SONAMEs do not match, the linker will fail to find the symbols.
Integration
dpkg-gensymbols is commonly used in conjunction with other packaging tools, such as:
- dpkg: The Debian package manager uses dpkg-gensymbols to generate symbol files for shared libraries included in packages.
- ldconfig: The ldconfig tool uses symbol files to update the shared library cache and resolve dynamic linker dependencies.
Related Commands
- readelf: Displays information about ELF files, including their symbol tables.
- objdump: Dumps the contents of object files, including their symbol tables.
- strip: Removes symbol information from ELF files.