strcpy

Copy strings

View other versions (3)

Contents

Interface
Description
Return Values
Security Considerations
See Also
Standards
History
Page Comments

Interface

#include <string.h>char  stpcpy (char *dst, const char *src)
char  strcpy (char * restrict dst, const char * restrict src)
char  strncpy (char * restrict dst, const char * restrict src, size_t len)

Description

The stpcpy and strcpy functions copy the string src to dst (including the terminating '\0' character.)

The strncpy function copies 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.

Return Values

The strcpy and strncpy functions return dst. The stpcpy function returns a pointer to the terminating '\0' character of dst.

Example:

Example - Copy strings

Problem

The following code sets chararray to "<code>abc\0\0\0</code>":

Workings

char chararray[6];
(void)strncpy(chararray, "abc", sizeof(chararray));

Security Considerations

The strcpy function is easily misused in a manner which enables malicious users to arbitrarily change a running program's functionality through a buffer overflow attack.

Standards

The strcpy and strncpy functions conform to ISO/IEC 9899:1990 ("ISO C90"). The stpcpy function is an MS-DOS and GNUism. The stpcpy function conforms to no standard.

History

The stpcpy function first appeared in FreeBSD 4.4 coming from 1998-vintage Linux.

char	`stpcpy` (char dst, const char src)
char	`strcpy` (char * restrict dst, const char * restrict src)
char	`strncpy` (char * restrict dst, const char * restrict src, size_t len)