use htonl convert a int number, and memcpy to a char*, but nothing

Asked Nov 06 '13 at 17:27

Active Nov 06 '13 at 18:19

Viewed 636 times

code like this:

int totalLen = 50;

int usTest = htons(totalLen);

char* strBuf = new char[totalLen ];

memcpy(strBuf,&usTest,sizeof(int));

after this,there is nothing in strBuf, why?

but if I put a big number, like 100000001, it will be OK?

what's the problem?

edited Nov 06 '13 at 18:19

asked Nov 06 '13 at 17:27

siriusan.dao

What value is in the variable `len`? – shf301 Nov 06 '13 at 17:38
the length of reqMsg! – siriusan.dao Nov 06 '13 at 17:50
memcpy(&strBuf + sizeof(int),reqMsg,len); shuld like this,even I remove this statement,it is still nothing in strBuf,so the problem is no on this statement. – siriusan.dao Nov 06 '13 at 17:51
i modify the code,try – siriusan.dao Nov 06 '13 at 18:20
Note that `htons()` returns an `uint16_t` (or equivalent), not an `int`, and as such, you should only `memcpy()` `sizeof(uint16_t)` bytes, not `sizeof(int)` bytes... – twalberg Nov 06 '13 at 20:24

0 Answers0