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       0     dest     NULL     Warning  Assignment takes integer from pointer without a cast      Source code   size t s strscpy char  dest  const char  src  const size t len           Copy the contents from src to dest        size t i   0      for i   0  i  lt  len  i         dest      src            Null terminate dest          dest     0        return i      Another question  I deliberately commented out the line that null terminates  However  it still correctly printed out the contents of the dest  The caller of this function would send the length of the string by either included the NULL or not  i e  strlen src    1 or stlen src    size t s strscpy char  dest  const char  src  const size t len           Copy the contents from src to dest        size t i   0         Don t copy the null terminator        for i   0  i  lt  len - 1  i         dest      src            Don t add the Null terminator            dest     0          return i

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

[c] null terminating a string

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