Show diagnostics of a file using libclang

diagnostic.cpp

#include <iostream>

#include <clang-c/Index.h>

using namespace std;

const char *flags[] = {
   "clang",
};

int main(int argc, const char *argv[]) {
    if (argc != 2) {
        cout << argv[0] << " file.cpp" << endl;
        return EXIT_FAILURE;
    }

    CXIndex index = clang_createIndex(0, 0);
    if (!index) {
        cerr << "createIndex failed" << endl;
        return EXIT_FAILURE;
    }

    unsigned options = clang_defaultEditingTranslationUnitOptions();

    CXTranslationUnit tu;
    CXErrorCode result = clang_parseTranslationUnit2FullArgv(
        index, argv[1], flags, sizeof(flags) / sizeof(flags[0]), nullptr, 0,
        options,
        &tu);

    if (result != CXError_Success) {
        cerr << "clang_parseTranslationUnit2FullArgv failed with error " << result << endl;
        return EXIT_FAILURE;
    }

    int failure = clang_reparseTranslationUnit(tu, 0, nullptr, options);

    if (failure) {
        cerr << "Reparse failed" << endl;
        return EXIT_FAILURE;
    }

    size_t num_diagnostics = clang_getNumDiagnostics(tu);

    for (size_t i = 0; i < num_diagnostics; ++i) {
        CXFile file;
        unsigned line;
        unsigned column;
        unsigned offset;
        CXDiagnostic diagnostic = clang_getDiagnostic(tu, i);
        CXSourceLocation location = clang_getDiagnosticLocation(diagnostic);
        clang_getExpansionLocation(location, &file, &line, &column, &offset);
        cout << "line " << line << " column " << column << " " << clang_getCString(clang_getDiagnosticSpelling(diagnostic)) << endl;
        clang_disposeDiagnostic(diagnostic);
    }

    return EXIT_SUCCESS;
}