c2664无法将参数2从'std :: string'转换为'const void *'

Question

This is where I call the function..

memcpy(dataHashResult,sha1.operator()(dataBuffer,16),16);

I changed

/// compute SHA1 of a memory block

std::string operator()(const void* data, size_t numBytes);

to

std::string operator()(BYTE* data, size_t numBytes);

the types of buffers are..

unsigned char dataBuffer[64];

unsigned char dataHashResult[64];

Any help would be appreciated ..I'm new to C++.. Thanks.

Answer 1

try this:

memcpy(dataHashResult,sha1.operator()(dataBuffer,16).c_str(),16);

The problem is that memcpy needs a pointer to copy from. Your original code gives it a std::string object . Luckily, std::string has a c_str() function that returns the "C-style" string, ie a const char* .