strcpy(3) BSD Library Functions Manual strcpy(3)
stpcpy, stpncpy, strcpy, strncpy -- copy strings
Standard C Library (libc, -lc)
#include <string.h> char * stpcpy(char *s1, const char *s2); char * stpncpy(char *restrict s1, const char *restrict s2, size_t n); char * strcpy(char *restrict s1, const char *restrict s2); char * strncpy(char *restrict s1, const char *restrict s2, size_t n);
The stpcpy() and strcpy() functions copy the string s2 to s1 (including the terminating `\0' character). The stpncpy() and strncpy() functions copy at most n characters from s2 into s1. If s2 is less than n characters long, the remainder of s1 is filled with `\0' characters. Otherwise, s1 is not terminated. The source and destination strings should not overlap, as the behavior is undefined.
The strcpy() and strncpy() functions return s1. The stpcpy() and stpncpy() functions return a pointer to the terminating `\0' character of s1. If stpncpy() does not terminate s1 with a NUL character, it instead returns a pointer to s1[n] (which does not necessarily refer to a valid memory location.)
The following sets chararray to ``abc\0\0\0'': char chararray; (void)strncpy(chararray, "abc", sizeof(chararray)); The following sets chararray to ``abcdef'': char chararray; (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 argument. 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. char buf; (void)strncpy(buf, input, sizeof(buf) - 1); buf[sizeof(buf) - 1] = '\0'; This could be better achieved using strlcpy(3), as shown in the following example: (void)strlcpy(buf, input, sizeof(buf));
The strcpy(), strncpy(), stpcpy(), and stpncpy() functions are easily misused in a manner which enables malicious users to arbitrarily change a running program's functionality through a buffer overflow attack. (See the FSA and EXAMPLES.) It is recommended that strlcpy(3) be used instead as a way to avoid such problems. strlcpy(3) is not defined in any standards, but it has been adopted by most major libc implementations.
The strcpy() and strncpy() functions conform to ISO/IEC 9899:1990 (``ISO C90''). The stpcpy() and stpncpy() functions conform to .
The stpcpy() function first appeared in FreeBSD 4.4, and stpncpy() was added in FreeBSD 8.0. BSD February 28, 2009 BSD
Mac OS X 10.8 - Generated Fri Aug 31 05:43:17 CDT 2012