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strncat.3

STRCAT

Section: Linux Programmer's Manual (3)
Updated: 2008-06-13
Index Return to Main Contents
 

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, strncat() 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)  

COLOPHON

This page is part of release 3.21 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/.


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
CONFORMING TO
SEE ALSO
COLOPHON

 

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