How Can I Demangle C `std::type_info::name()` Results?

Demangling the Result of std::type_info::name

The type_info class in C provides a method to retrieve the name of a type, but the returned name is often mangled. This makes it difficult to extract useful information from the name. To address this issue, we can utilize a technique known as demangling.

Demangling Process

Demangling involves converting the mangled name back into its original, human-readable form. This process can be achieved using the abi::__cxa_demangle() function provided by the C runtime environment. However, this function is only available in certain compilers, such as GCC.

Implementation for GCC

For GCC, the demangling process can be implemented as shown below:

#include <typeinfo>
#include <cxxabi.h>

std::string demangle(const char* mangled_name) {
    int status = -4;
    char* demangled_name = abi::__cxa_demangle(mangled_name, NULL, NULL, &status);
    if (status == 0) {
        std::string result(demangled_name);
        free(demangled_name);
        return result;
    }
    return mangled_name;
}

Usage

With the demangling function in place, you can retrieve the demangled name of a type as follows:

std::string demangled_name = demangle(typeid(int).name());

Non-GCC Compilers

If you are not using GCC, you may need to find an alternative library or technique for demangling the type names.

Automatic Type Demangling in Logging

The technique described above can be integrated into logging systems to automatically demangle type names, making it easier to understand the calling context. This can be particularly useful for debugging purposes.

Additional Considerations

Note that demangling is not always possible or practical, especially for complex or nested types. In such cases, you may need to use other approaches to extract meaningful information from the type_info object.

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