null terminating a string

Question

gcc 4.4.4 c89

What is the standard way to null terminate a string? When I use the NULL I get a warning message.

*dest++ = 0; 
*dest++ =          


        

Answer 1

From the comp.lang.c FAQ: http://c-faq.com/null/varieties.html

In essence: NULL (the preprocessor macro for the null pointer) is not the same as NUL (the null character).

Answer 2

'\0' is the way to go. It's a character, which is what's wanted in a string and has the null value.

When we say null terminated string in C/C++, it really means 'zero terminated string'. The NULL macro isn't intended for use in terminating strings.

Answer 3

Be very careful: NULL is a macro used mainly for pointers. The standard way of terminating a string is:

char *buffer;
...
buffer[end_position] = '\0';

This (below) works also but it is not a big difference between assigning an integer value to a int/short/long array and assigning a character value. This is why the first version is preferred and personally I like it better.

buffer[end_position] = 0; 

Answer 4

To your first question: I would go with Paul R's comment and terminate with '\0'. But the value 0 itself works also fine. A matter of taste. But don't use the MACRO NULLwhich is meant for pointers.

To your second question: If your string is not terminated with\0, it might still print the expected output because following your string is a non-printable character in your memory. This is a really nasty bug though, since it might blow up when you might not expect it. Always terminate a string with '\0'.