linux man page for strncat

STRCAT(3)						     Linux Programmer's Manual							 STRCAT(3)

NAME
       strcat, strncat - concatenate two strings

SYNOPSIS
       #include <string.h>

       char *strcat(char *dest, const char *src);

       char *strncat(char *dest, const char *src, size_t n);

DESCRIPTION
       The  strcat() function appends the src string to the dest string, overwriting the null byte ('') at the end of dest, and then adds a ter-
       minating null byte.  The strings may not overlap, and the dest string must have enough space for the result.

       The strncat() function is similar, except that

       *  it will use at most n characters from src; and

       *  src does not need to be null-terminated if it contains n or more characters.

       As with strcat(), the resulting string in dest is always null-terminated.

       If src contains n or more characters, strncat() writes n+1 characters to dest (n from src plus the terminating null byte).  Therefore,  the
       size of dest must be at least strlen(dest)+n+1.

       A simple implementation of strncat() might be:

	   char*
	   strncat(char *dest, const char *src, size_t n)
	   {
	       size_t dest_len = strlen(dest);
	       size_t i;

	       for (i = 0 ; i < n && src[i] != '' ; i++)
		   dest[dest_len + i] = src[i];
	       dest[dest_len + i] = '';

	       return dest;
	   }

RETURN VALUE
       The strcat() and strncat() functions return a pointer to the resulting string dest.

CONFORMING TO
       SVr4, 4.3BSD, C89, C99.

SEE ALSO
       bcopy(3), memccpy(3), memcpy(3), strcpy(3), string(3), strncpy(3), wcscat(3), wcsncat(3)

COLOPHON
       This  page is part of release 3.27 of the Linux man-pages project.  A description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

GNU
								    2010-09-20								 STRCAT(3)