关于valgrind的 “Conditional jump or move depends on uninitialised value(s)”

关于valgrind的 “Conditional jump or move depends on uninitialised value(s)”：

valgrind在报这个错误的时候程序未必有bug，如下例：

代码

// test.cpp
#include  < iostream >
using   namespace  std;
bool  ptr( char   * testptr)
{
         int  i = 0 ;
         if (i  ==   0 ){
                memcpy(testptr, " Hello " , 5 );
                 return   true ;
        }
         return   false ;
}

int  main( int  argc,  const   char   * argv[])
{
         char   * p  =   new   char  [ 10 ];
         if (ptr(p)){
                printf( " %s\n " ,p);
        }

        delete [] p;

         return   0 ;
}

执行：
g++ test.cpp -Wall
valgrind --tool=memcheck --leak-check=full --show-reachable=yes ./a.out

就会报下面的错：

==8472==
==8472== Conditional jump or move depends on uninitialised value(s)
==8472==    at 0x4906507: strlen (mac_replace_strmem.c:243)
==8472==    by 0x3D26142A0A: vfprintf (in /lib64/tls/libc-2.3.4.so)
==8472==    by 0x3D26148157: printf (in /lib64/tls/libc-2.3.4.so)
==8472==    by 0x4009A6: main (in /home/maoqi/private/cpp/a.out)
Hello
==8472==
==8472== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 5 from 2)
==8472== malloc/free: in use at exit: 0 bytes in 0 blocks.
==8472== malloc/free: 1 allocs, 1 frees, 10 bytes allocated.
==8472== For counts of detected errors, rerun with: -v
==8472== All heap blocks were freed -- no leaks are possible.

因此在遇到这种错误的时候需要仔细分析。