Future page man de str[n]cpy

Pour le strncpy, par contre, la partie NOTE et BUG a été conservée.


STRCPY(3) Linux Programmer's Manual STRCPY(3)

NAME
strcpy, strncpy - copy a string

SYNOPSIS
#include <string.h>

char *strcpy(char *dest, const char *src);

char *strncpy(char *dest, const char *src, size_t n);

DESCRIPTION
The strcpy() function copies the string pointed to by
src, including the terminating null byte ('\0'), to the
buffer pointed to by dest. The strings may not overlap,
and the destination string dest must be large enough to
receive the copy.

The strncpy() function is similar, except that at most n
bytes of src are copied. Warning: If there is no null
byte among the first n bytes of src, the string placed in
dest will not be null terminated.

If the length of src is less than n, strncpy() pads the
remainder of dest with null bytes.

A simple implementation of strncpy() might be:

char*
strncpy(char *dest, const char *src, size_t n){
size_t i;

for(i = 0 ; i < n && src[i] != '\0' ; i++)
dest[i] = src[i];
for( ; i < n ; i++)
dest[i] = '\0';

return dest;
}

RETURN VALUE
The strcpy() and strncpy() functions return a pointer to
the destination string dest.

CONFORMING TO
SVr4, 4.3BSD, C89, C99.

NOTES
Some programmers consider strncpy() to be inefficient and
error prone. If the programmer knows (i.e., includes
code to test!) that the size of dest is greater than the
length of src, then strcpy() can be used.

If there is no terminating null byte in the first n char-
acters of src, strncpy() produces an unterminated string
in dest. Programmers often prevent this mistake by forc-
ing termination as follows:

strncpy(buf, str, n);
if (n > 0)
buf[n - 1]= ' ';

BUGS
If the destination string of a strcpy() is not large
enough (that is, if the programmer was stupid or lazy,
and failed to check the size before copying) then any-
thing might happen. Overflowing fixed length strings is
a favourite cracker technique.

SEE ALSO
bcopy(3), memccpy(3), memcpy(3), memmove(3), wcscpy(3),
wcsncpy(3)
--
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Travesties par des gueux pour exciter des sots
IF -- Rudyard Kipling (Trad. André Maurois)