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：

//

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。