Returns non-zero if the given cursor points to a symbol marked with external_source_symbol attribute.
\param language If non-NULL, and the attribute is present, will be set to the 'language' string from the attribute.
\param definedIn If non-NULL, and the attribute is present, will be set to the 'definedIn' string from the attribute.
\param isGenerated If non-NULL, and the attribute is present, will be set to non-zero if the 'generated_declaration' is set in the attribute.
See Implementation
Returns non-zero if the given cursor points to a symbol marked with external_source_symbol attribute.
\param language If non-NULL, and the attribute is present, will be set to the 'language' string from the attribute.
\param definedIn If non-NULL, and the attribute is present, will be set to the 'definedIn' string from the attribute.
\param isGenerated If non-NULL, and the attribute is present, will be set to non-zero if the 'generated_declaration' is set in the attribute.