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STRCPY(3) NetBSD Library Functions Manual STRCPY(3)
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stpcpy, stpncpy, strcpy, strncpy -- copy strings
Standard C Library (libc, -lc)
stpcpy(char * restrict dst, const char * restrict src);
stpncpy(char * restrict dst, const char * restrict src, size_t len);
strcpy(char * restrict dst, const char * restrict src);
strncpy(char * restrict dst, const char * restrict src, size_t len);
The stpcpy() and strcpy() functions copy the string src to dst (including
the terminating `\0' character).
The stpncpy() and strncpy() functions copy at most len characters from
src into dst. If src is less than len characters long, the remainder of
dst is filled with `\0' characters. Otherwise, dst is not terminated.
The strings src and dst may not overlap.
The strcpy() and strncpy() functions return dst. The stpcpy() and
stpncpy() functions return a pointer to the terminating `\0' character of
dst. If stpncpy() does not terminate dst with a NUL character, it
instead returns a pointer to dst[len] (which does not necessarily refer
to a valid memory location.)
The following sets chararray to ``abc\0\0\0'':
(void)strncpy(chararray, "abc", sizeof(chararray));
The following sets chararray to ``abcdef'':
(void)strncpy(chararray, "abcdefgh", sizeof(chararray));
Note that it does not NUL-terminate chararray because the length of the
source string is greater than or equal to the length parameter.
strncpy() only NUL-terminates the destination string when the length of
the source string is less than the length parameter.
The following copies as many characters from input to buf as will fit and
NUL-terminates the result. Because strncpy() does not guarantee to
NUL-terminate the string itself, this must be done explicitly.
(void)strncpy(buf, input, sizeof(buf) - 1);
buf[sizeof(buf) - 1] = '\0';
This could be better and more simply achieved using strlcpy(3), as shown
in the following example:
(void)strlcpy(buf, input, sizeof(buf));
Note that because strlcpy(3) is not defined in any standards, it should
only be used when portability is not a concern.
bcopy(3), memccpy(3), memcpy(3), memmove(3), strlcpy(3), wcscpy(3)
The strcpy() and strncpy() functions conform to ISO/IEC 9899:1999
(``ISO C99''). The stpcpy() and stpncpy() functions conform to IEEE Std
The stpcpy() and stpncpy() functions first appeared in NetBSD 6.0.
The strcpy() and stpcpy() functions are easily misused in a manner which
enables malicious users to arbitrarily change a running program's func-
tionality through a buffer overflow attack.
NetBSD 9.99 April 1, 2015 NetBSD 9.99