STRCAT(3)

NAME
strcat, strncat - concatenate strings

SYNOPSIS
#include <string.h>
char *
strcat(char *s, const char *append);
char *
strncat(char *s, const char *append, size_t count);

DESCRIPTION
The strcat() and strncat() functions append a copy of the NUL-terminated string append to the end of the NUL-terminated string s, then add a terminating ‘\0’. The string s must have sufficient space to hold the result.

The strncat() function appends not more than count characters where space for the terminating ‘\0’ should not be included in count.

RETURN VALUES
The strcat() and strncat() functions return the pointer s.

EXAMPLES
The following appends “abc” to chararray:

    char *letters = "abcdefghi";
    (void)strncat(chararray, letters, 3);

The following example shows how to use strncat() safely in conjunction with strncpy(3).

    char buf[BUFSIZ];
    char *input, *suffix;
    (void)strncpy(buf, input, sizeof(buf) - 1);
    buf[sizeof(buf) - 1] = '\0';
    (void)strncat(buf, suffix, sizeof(buf) - 1 - strlen(buf));

The above will copy as many characters from input to buf as will fit. It then appends as many characters from suffix as will fit (or none if there is no space). For operations like this, the strlcpy(3) and strlcat(3) functions are a better choice, as shown below.

    (void)strlcpy(buf, input, sizeof(buf));
    (void)strlcat(buf, suffix, sizeof(buf));

SEE ALSO
bcopy(3), memccpy(3), memcpy(3), memmove(3), strcpy(3), strlcpy(3), wcscat(3), wcslcpy(3)

STANDARDS
The strcat() and strncat() functions conform to ansiC.

HISTORY
The strcat() and strncat() functions first appeared in AT&T UNIX.