How to Retrieve a Raw Data Pointer from a std::vector?

Retrieving Raw Data Pointer from std::vector

Problem:

You seek to use a std::vector as a char array within a function accepting a void pointer. Attempts to pass the vector directly or through its begin() iterator have resulted in incorrect data or compiler warnings.

Solution:

To access the raw data of a std::vector, obtain the address of its initial element using one of the following methods:

• &something[0] or &something.front() - returns the address of the element at index 0.
• &*something.begin() - returns the address of the element pointed to by the begin() iterator.

In C 11 onwards, an additional option is available:

• &something.data() - returns the address of the initial element, ensuring safety even for empty containers.

Examples:

void process_data(const void *data);

std::vector<char> something;

// Cast the raw data pointer to char* for compatibility.
char *data_ptr = reinterpret_cast<char*>(something.data());
process_data(data_ptr);

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