| STRCAT(3) | Library Functions Manual | STRCAT(3) |
strcat, strncat —
#include <string.h>
char *
strcat(char
* restrict s, const char
* restrict append);
char *
strncat(char
* restrict s, const char
* restrict append, size_t
count);
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.
strcat() and strncat()
functions return the pointer s.
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));
strcat() and strncat()
functions conform to ISO/IEC 9899:1999
(“ISO C99”).
| August 11, 2002 | NetBSD 9.4 |