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 ('\0') at the end of dest, and then adds a terminating 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, strcat() 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] != '\0' ; i++)
        dest[dest_len + i] = src[i];
    dest[dest_len + i] = '\0';
    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), strncpy(3), wcscat(3), wcsncat(3)