如何在 C++ 中使用 Void 而不会出现关于参数的错误

Question

我正在尝试使用 C++ 在 ROOT 中创建一个简单的树运行使用这里的教程：https://www.niser.ac.in/sercehep2017/notes/RootTutorial_TTree.pdf.

但是，为什么会出现此错误：

Processing examples/tree_example1.C("../trisignal/Events/run_01/tag_1_delphes_events.root")...
input_line_9:2:2: error: no matching function for call to 'tree_example1'
 tree_example1("../trisignal/Events/run_01/tag_1_delphes_events.root") /* invoking function corresponding to '.x' */
 ^~~~~~~~~~~~~
/mnt/c/1/MG5_aMC_v2_6_6/Delphes/examples/tree_example1.C:12:6: note: candidate function not viable: requires 0 arguments, but 1 was provided
void tree_example1 ()

我只是想运行一个创建 TTree 的简单代码。这是我的代码：

/*
#ifdef __CLING__
R__LOAD_LIBRARY(libDelphes)
#include "classes/DelphesClasses.h"
#include "external/ExRootAnalysis/ExRootTreeReader.h"
#include "external/ExRootAnalysis/ExRootResult.h"
#else
class ExRootTreeReader;
class ExRootResult;
#endif
*/
void tree_example1 ()
{
  //gSystem->Load("libDelphes");

  // Create chain of root trees
  //TChain chain("Delphes");
  //chain.Add(inputFile);
  //Open the input file and Create a simple tree
  TFile *f = new TFile("eventstrial.root", "RECREATE");
  TTree *tree = new TTree("T", "simple tree");
  //TTree *tree = &chain;
  TRandom r;

  //Filling Histograms
  TH1F *hist = new TH1F("hist", "", 100, 0., 2.);
    //Set up the variables
  Float_t px, py, pz, pt;
  Double_t random;
  UShort_t i;

    //Set Variables to Tree's Branches

  tree->Branch("px", &px, "px/F");
  tree->Branch("py", &py, "py/F");
  tree->Branch("pz", &py, "py/F");
  tree->Branch("pt", &pt, "pt/F");
  tree->Branch("random", &random, "random/D");

  for (i = 0; i < 10000; i++)
  {
    r.Rannor(px,py);
    pt = std::sqrt(px*px + py*py);
    tree->Fill();
  }
  f->Write();
  f->Close();
   tree->Draw("pt>>hist");
   hist->SetLineColor(3);
   hist->Draw("same");
}

我在我的 ROOT 终端中输入：root -l 'examples/tree_example1.C("../trisignal/Events/run_01/tag_1_delphes_events.root")'

如果我写 root -l tree_example1.C

我收到这个错误：

root [0]
Processing tree_example1.C...

 *** Break *** segmentation violation
 Generating stack trace...
 0x00007fdcdda680a0 in cling::IncrementalExecutor::executeWrapper(llvm::StringRef, cling::Value*) const + 0x380 from /home/cucip/builddir/lib/libCling.so
 0x00007fdcdd9fae77 in cling::Interpreter::RunFunction(clang::FunctionDecl const*, cling::Value*) + 0xa7 from /home/cucip/builddir/lib/libCling.so
 0x00007fdcdd9fc4df in cling::Interpreter::EvaluateInternal(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, cling::CompilationOptions, cling::Value*, cling::Transaction**, unsigned long) + 0x1df from /home/cucip/builddir/lib/libCling.so
 0x00007fdcddac61f1 in cling::MetaSema::actOnxCommand(llvm::StringRef, llvm::StringRef, cling::Value*) + 0x591 from /home/cucip/builddir/lib/libCling.so
 0x00007fdcddad6084 in cling::MetaParser::isXCommand(cling::MetaSema::ActionResult&, cling::Value*) + 0x194 from /home/cucip/builddir/lib/libCling.so
 0x00007fdcddad7476 in cling::MetaParser::isCommand(cling::MetaSema::ActionResult&, cling::Value*) + 0xa6 from /home/cucip/builddir/lib/libCling.so
 0x00007fdcddabf64b in cling::MetaProcessor::process(llvm::StringRef, cling::Interpreter::CompilationResult&, cling::Value*, bool) + 0x10b from /home/cucip/builddir/lib/libCling.so
 0x00007fdcdd97b68e in <unknown> from /home/cucip/builddir/lib/libCling.so
 0x00007fdcdd98fe72 in <unknown> from /home/cucip/builddir/lib/libCling.so
 0x00007fdcdd984537 in <unknown> from /home/cucip/builddir/lib/libCling.so
 0x00007fdce3112908 in TApplication::ExecuteFile(char const*, int*, bool) at /home/cucip/root-6.18.04/core/base/src/TApplication.cxx:1156 from /home/cucip/builddir/lib/libCore.so
 0x00007fdce31120ac in TApplication::ProcessLine(char const*, bool, int*) at /home/cucip/root-6.18.04/core/base/src/TApplication.cxx:1007 from /home/cucip/builddir/lib/libCore.so
 0x00007fdce35e18e2 in TRint::ProcessLineNr(char const*, char const*, int*) at /home/cucip/root-6.18.04/core/rint/src/TRint.cxx:762 from /home/cucip/builddir/lib/libRint.so
 0x00007fdce35e31d9 in TRint::Run(bool) at /home/cucip/root-6.18.04/core/rint/src/TRint.cxx:421 from /home/cucip/builddir/lib/libRint.so
 0x00007fdce3c00a0c in <unknown> from /home/cucip/builddir/bin/root.exe
 0x00007fdce2571b97 in __libc_start_main + 0xe7 from /lib/x86_64-linux-gnu/libc.so.6
 0x00007fdce3c00a6a in _start + 0x2a from /home/cucip/builddir/bin/root.exe
Root >

Answer 1

正如编译器所说：

需要 0 个参数，但提供了 1 个 void tree_example1 ()

您调用 tree_example1 时使用了一个参数而不是零。重新定义函数以接受路径

如何在 C++ 中使用 Void 而不会出现关于参数的错误

How to use Void in C++ without getting an Error about Argument

c++

tuples

void

root-framework