Dump source ranges for diagnostics using libclang.

main.c

#include <clang-c/Index.h>
#include <stdio.h>

void parseMalformedFile(char* source) {
  CXIndex index = clang_createIndex(
      /* excludeDeclarationsFromPCH */ 0,
      /* displayDiagnostics */ 0);
  const char *args[] = {
    "-I/usr/include",
    "-I.",
    "-fdiagnostics-print-source-range-info",
  };
  int numArgs = sizeof(args) / sizeof(*args);
  CXTranslationUnit tu = clang_parseTranslationUnit(index, source, args, numArgs, NULL, 0, CXTranslationUnit_None);

  unsigned diagnosticCount = clang_getNumDiagnostics(tu);
  printf("Diagnostic count: %d\n", diagnosticCount);

  for (unsigned i = 0; i < diagnosticCount; i++) {
    CXDiagnostic diagnostic = clang_getDiagnostic(tu, i);

    CXString text = clang_getDiagnosticSpelling(diagnostic);
    printf("\nDiagnostic spelling: %s\n", clang_getCString(text));
    clang_disposeString(text);

    unsigned options = CXDiagnostic_DisplaySourceLocation |
        CXDiagnostic_DisplayColumn |
	CXDiagnostic_DisplayOption |
        CXDiagnostic_DisplaySourceRanges |
        CXDiagnostic_DisplayCategoryId |
        CXDiagnostic_DisplayCategoryName;
    CXString formattedDiagnostic = clang_formatDiagnostic(diagnostic, options);
    printf("Formatted diagnostic: %s\n", clang_getCString(formattedDiagnostic));
    clang_disposeString(formattedDiagnostic);

    // List the ranges.
    unsigned rangeCount = clang_getDiagnosticNumRanges(diagnostic);
    if (rangeCount == 0) {
      printf("No source ranges for diagnostic.\n");
    }
    for (unsigned j = 0; j < rangeCount; j++) {
      CXSourceRange range = clang_getDiagnosticRange(diagnostic, j);

      unsigned startLine, startColumn;
      CXSourceLocation start = clang_getRangeStart(range);
      clang_getSpellingLocation(start, /* file */ NULL, &startLine, &startColumn, /* offset */ NULL);

      unsigned endLine, endColumn;
      CXSourceLocation end = clang_getRangeEnd(range);
      clang_getSpellingLocation(end, /* file */ NULL, &endLine, &endColumn, /* offset */ NULL);

      printf("Range: %d,%d;%d,%d\n", startLine, startColumn, endLine, endColumn);
    }

    clang_disposeDiagnostic(diagnostic);
  }

  clang_disposeTranslationUnit(tu);
  clang_disposeIndex(index);
}

int main(int argc, char **argv) {
  if (argc != 2) {
    printf("ERROR: Must specify a single file to compile.\n");
    return 1;
  }

  char* source = argv[1];
  parseMalformedFile(source);
  return 0;
}

Ther is an error, you need add -I/usr/lib/llvm-3.8/lib/clang/3.8.0/include (the number depend on your libclang version)