gdb 不会与 #include 指令排成一行

Question

The problem is that, when I set a breakpoint at the line of the #include, gdb just ignore the line and stop at the next instruction in the main (I compiled the main.cpp with g++ -g -O2 -std=c++11 ).

The program works perfect (-O2 doesn't affect the result at all), but I want to check what exactly does something inside that file, but I can't because gdb doesn't let me enter the code inside the file.

How can I debug code inside other file? Is it even possible?

Edit : Here is the code

main.cpp

#include <iostream>
#include <cstdlib>
#include <chrono>
#include "inc/includes.h"

template <class T>
void PrintVector(T* vector, int size){
  for (int i=0; i<size; ++i){
    std::cout << vector[i] << " ";
  }
  std::cout << std::endl;
}

template <class T>
void CheckTime(void (*f)(T*&, int), T* &vector, int size){
  std::chrono::high_resolution_clock::time_point tantes, tdespues;
  std::chrono::duration<double> transcurrido;

  tantes = std::chrono::high_resolution_clock::now();
  (*f)(vector, size);
  tdespues = std::chrono::high_resolution_clock::now();

  transcurrido = std::chrono::duration_cast<std::chrono::duration<double>(tdespues - tantes);

  std::cout << size << " " << transcurrido.count() << std::endl;
}

int main(int argc, char * argv[]){
  if (argc != 2){
    std::cerr << "Formato " << argv[0] << " <num_elem>" << std::endl;
    return -1;
  }

  int n = atoi(argv[1]);
  int range;

#if defined RADIXSORTLSD || defined RADIXSORTMSD
  unsigned short * array = new unsigned short[n];
  range = (n<65536)?n:65536;
#else
  unsigned int * array = new unsigned int[n];
  range = n;
#endif
  srand(time(0));

  for (int i = 0; i < n; i++){
    array[i] = rand()%range;
  }

#ifdef PRINT
  PrintVector(array, n);
#endif

#include "inc/select.h"  //Here is the problem for debugging

#ifdef PRINT
  PrintVector(array, n);
#endif
}

includes.h

#include "../src/radixsortlsd.cpp"
#include "../src/radixsortmsd.cpp"
#include "../src/mergesort.cpp"
#include "../src/bitonicsort.cpp"
#include "../src/insertion.cpp"
#include "../src/slowsort.cpp"
#include "../src/selection.cpp"

select.h This is the code I want to debug. I decided to separate it from the main because it will grow a lot.

// The calls to CheckTime takes the first parameter as the direction to a function, previously defined inside the cpps of includes.h
#ifdef RADIXSORTLSD
CheckTime(&RadixSortLSD, array, n);
#endif
#ifdef RADIXSORTMSD
CheckTime(&RadixSortMSD, array, n);
#endif
#ifdef MERGESORT
CheckTime(&MergeSort, array, n);
#endif
#ifdef INSERTION
CheckTime(&Insertion, array, n);
#endif
#ifdef SLOWSORT
CheckTime(&SlowSort, array, n);
#endif
#ifdef SELECTION
CheckTime(&Selection, array, n);
#endif
#ifdef BITONICSORT
CheckTime(&BitonicSort, array, n);
#endif

I hope this help. Note that everything compiles great and works great (I made sure that the macros I defined when compiling are the correct ones)

Note : By debugging (not the right word) I meant checking how a function works (a function I don't fully understand).

Answer 1

Possibly you could break at MyFunction(), then run 'bt' command to see the stack. Then you see, is there any additional stack frame or what stack frames consist of in terms of source files, it might help

Answer 2

First of all:

A include is a preprocessor directive which never generates code. Debuggers can stop only on things which can be executed. Including a file works during compilation, not during runtime.

The next:

Your included files will define some values, functions, classes and a lot other. So you must give the debugger an idea where to stop.

And at all: Including 'cpp' files is really trash! There are only very seldom reasons to do this.

But ok, how to proceed:

If your header file ( or included cpp file ) provides a function, you simply can do a break Func and run your program. No need to open any file in a gui for gdb before.

If you want to look inside the included files, you also can list myheader.h:1 . The 1 one is the line of code you want to start looking into the file.

And a hint: Please provide much smaller code examples which persons can compile for themselves to give you more detailed help. You example is really bad to understand!

Example session:

Header: fh

#include <stdlib.h>

void g(void)
{
    malloc(4000);
}

void f(void)
{
    malloc(2000);

}

main.cpp:

#include "f.h"
 int main(void)
{
    int i;
    int* a[10];

    for (i = 0; i < 10; i++) {
        a[i] = (int*)malloc(1000);
    }

    f();

    g();

    for (i = 0; i < 10; i++) {
        free(a[i]);
        return 0;
    }


}

Example session:

> gdb prog
gdb) break f
Breakpoint 1 at 0x40061a: file main.cpp, line 10.
(gdb) run
Starting program: /home/xxx/go 

Breakpoint 1, f () at f.h:10
 10     malloc(2000);
(gdb) list
 5      malloc(4000);
 6  }
 7  
 gdb ) 

Now you can walk through your subroutine with step .