此代码中的内存泄漏在哪里以及如何解决？

在我的项目中,我有一个方法,从整数(使用strcat)创建一个字符串并将其写入文件.不幸的是它确实有内存泄漏.在跟踪泄漏时,我将代码简化为以下内容.我似乎无法找到甚至修复它.这是代码:

#include 
#include 
#include 
int main(int argc, char* argv[] )
{
 char* output = "\0";
 int counter = 5;
  while(counter > 0)
  {
      char buffer[20];
      sprintf(buffer, "%u", counter);
      char* temp;
      temp = malloc((strlen(output) + strlen(buffer) + 1));
      strcpy(temp, buffer);
      strcat(temp, output);
      char* oldmemory = output;
      output = temp;
      free(oldmemory);
      counter--;
  }
printf("output: %s\n", output);
free(output);
return 0;
}

Valgrind回归:

==7125== Memcheck, a memory error detector
==7125== Copyright (C) 2002-2009, and GNU GPL'd, by Julian Seward et al.
==7125== Using Valgrind-3.6.0.SVN-Debian and LibVEX; rerun with -h for copyright info
==7125== Command: ./foo
==7125== Parent PID: 4455
==7125== 
==7125== Invalid free() / delete / delete[]
==7125==    at 0x4024B3A: free (vg_replace_malloc.c:366)
==7125==    by 0x8048662: main (foo.c:20)
==7125==  Address 0x8048780 is not stack'd, malloc'd or (recently) free'd
==7125== 
==7125== 
==7125== HEAP SUMMARY:
==7125==     in use at exit: 0 bytes in 0 blocks
==7125==   total heap usage: 5 allocs, 6 frees, 20 bytes allocated
==7125== 
==7125== All heap blocks were freed -- no leaks are possible
==7125== 
==7125== For counts of detected and suppressed errors, rerun with: -v
==7125== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 15 from 8)

内存泄漏在哪里？我该如何解决？

#include 
#include 
int main(int argc, char* argv[] )
{
 char* output = "\0";

字符串文字是'\ 0'自动终止,您不需要添加它.

 int counter = 5;
  while(counter > 0)
  {
      char buffer[20];
      sprintf(buffer, "%u", counter);
      char* temp;
      temp = malloc((strlen(output) + strlen(buffer) + 1));
      strcpy(temp, buffer);
      strcat(temp, output);
      char* oldmemory = output;
      output = temp;
      free(oldmemory);

第一次free()调用它时,它释放输出的初始值,这是一个指向字符串文字的指针"\0".调用free()返回的有效指针以外的任何内容,*alloc()或者NULL是未定义的行为.

      counter--;
  }
printf("output: %s\n", output);
free(output);
return 0;
}

valgrind报道:

==7125== Invalid free() / delete / delete[]
==7125==    at 0x4024B3A: free (vg_replace_malloc.c:366)
==7125==    by 0x8048662: main (foo.c:20)
==7125==  Address 0x8048780 is not stack'd, malloc'd or (recently) free'd

这不是内存泄漏; 这是无效的free().