STRCAT(3) | Linux Programmer's Manual | STRCAT(3) |
NAME
strcat, strncat - concatenate two stringsSYNOPSIS
#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 terminating 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. If dest is not large enough, program behavior is unpredictable; buffer overruns are a favorite avenue for attacking secure programs.The strncat() function is similar, except that
- *
- it will use at most n bytes from src; and
- *
- src does not need to be null-terminated if it contains n or more bytes.
As with strcat(), the resulting string in dest is always null-terminated.
If src contains n or more bytes, strncat() writes n+1 bytes 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.NOTES
Some systems (the BSDs, Solaris, and others) provide the following function:size_t strlcat(char *dest, const char *src, size_t size);
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 3.53 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/.2012-07-19 | GNU |