STRCAT(3) BSD Library Functions Manual STRCAT(3)NAME
strcat, strncat — concatenate strings
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <string.h>
char *
strcat(char * restrict s, const char * restrict append);
char *
strncat(char * restrict s, const char * restrict 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 ter‐
minating ‘\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 ALSObcopy(3), memccpy(3), memcpy(3), memmove(3), strcpy(3), strlcat(3),
strlcpy(3)STANDARDS
The strcat() and strncat() functions conform to ISO/IEC 9899:1999
(“ISO C99”).
BSD August 11, 2002 BSD
