Memset - Definitions

Definitions

A string is a contiguous sequence of characters terminated by and including the first null character (written '\0' and corresponding to the ASCII character NUL). In C, there are two types of strings: string, which is sometimes called byte string, and wide string. A byte string contains the type chars as code units (one char is at least 8 bits), whereas a wide string contains the type wchar_t as code units.

A common misconception is that all char arrays are strings, because string literals are converted to arrays during the compilation (or translation) phase. It is important to remember that a string ends at the first null character. An array or string literal that contains a null character before the last byte therefore contains a string, or possibly several strings, but is not itself a string. Conversely, it is possible to create a char array that is not null-terminated and is thus not a string. char is often used as integer when needing to save memory, for example when having an array of booleans.

The term pointer to a string is used in C to describe a pointer to the initial (lowest-addressed) byte of a string. In C, pointers are used to pass strings to functions. Documentation (including this page) will often use the term string to mean pointer to a string.

The term length of a string is used in C to describe the number of bytes preceding the null character. strlen is a standardised function commonly used to determine the length of a string.