When to use std::vector<unsigned char> vs. std::vector<char>

Which of o开发者_运维知识库ne of these is best suited for managing a character buffer that can be easily converted to std::string and passed to and used ( i.e. read / write ) in C functions

std::vector<unsigned char> 
std::vector<char>

char's signedness depends on the compiler.¹

It can represent a unsigned char or signed char. Which type is used when representing a string is dependent on the compiler - therefore you should use char for portability, and clarity. If that isn't enough, would the less typing needed when writing char convince you? :)

Again, the compiler thinks strings are of type char *, which can be equivalent to unsigned char * or signed char *. If you're going to be working with strings use std::vector<char>.

¹ char is the only type with this behavior.

References

¹ Is char signed or unsigned by default?

char is more compatible with strings than unsigned char. String literals are char[] and std::string is actually std::basic_string<char>.

Both are equally well suited. If these are character buffers, as opposed to bytes, I would go with std::vector< char >.

You can create a string from a vector of any of those types with std::string( v.begin(), b.end() );

char, unsigned char, and signed char are 3 distinct types.

• Use an unsigned char or a signed char when dealing with numbers.
• Use a regular char when dealing with strings.

Thus, you should use a char.