-exported_symbol[s_list] command line option

The "-exported_symbol[s_list]" command line option is used in the process of linking object files to create an executable file or a shared library in C++. It allows the programmer to specify a list of symbols that should be exported from the resulting binary.

When a C++ program is compiled, each source file is compiled separately into an object file. These object files contain the compiled code for the functions and variables defined in the source file. When these object files are linked together, the linker combines all the object files into a single executable or shared library.

During the linking process, the linker will discard any symbols that are not used by the program. By using the "-exported_symbol[s_list]" command line option, the programmer can ensure that certain symbols are not discarded by the linker, and are instead made available for use by other programs that link against the resulting binary.

For example, if a programmer wanted to export a function called "foo" from their shared library, they could use the following command line option:

-exported_symbol foo

This would ensure that the symbol "foo" is not discarded by the linker, and is available for other programs to use.