STRCPY(3)

STRCPY(3) | Library Functions Manual | STRCPY(3)

# NAME

`stpcpy`, `strcpy` — copy strings

# LIBRARY

Standard C Library (libc, -lc)

# SYNOPSIS

`#include <string.h>`

char *
`stpcpy`(char * restrict dst, const char * restrict src);

char *
`strcpy`(char * restrict dst, const char * restrict src);

# DESCRIPTION

The `stpcpy`() and `strcpy`() functions copy the string src to dst, including the terminating NUL byte.

The strings src and dst may not overlap. The string src must be terminated by a NUL byte. The memory for dst must have space for `strlen`(src) `+ 1` bytes.

# RETURN VALUES

The `strcpy`() function returns dst.

The `stpcpy`() function returns a pointer to the terminating NUL byte of dst.

# SEE ALSO

bcopy(3), memccpy(3), memcpy(3), memmove(3), strlcpy(3), strncpy(3), wcscpy(3)

# STANDARDS

The `strcpy`() function conforms to ISO/IEC 9899:1999 (“ISO C99”).

The `stpcpy`() function conforms to IEEE Std 1003.1-2008 (“POSIX.1”).

# HISTORY

The `stpcpy`() function first appeared in NetBSD 6.0.

# SECURITY CONSIDERATIONS

The `strcpy`() and `stpcpy`() functions copy until a NUL terminator without any bounds checks on the size of the input or output buffers. If the input buffer is missing a NUL terminator, or the input string is longer than the output buffer, this can lead to crashes or security vulnerabilities from buffer overruns, including disclosure of secrets in memory and arbitrary code execution.

The strlcpy(3) function is a safer replacement for `strcpy`() which allows the caller to specify the space allocated for dst. strlcpy(3), or snprintf(3) with a format string of `"%s"`, should be used instead of `strcpy`() and `stpcpy`() wherever possible to avoid buffer overruns in dst. (However, they still require src to be NUL-terminated.)

August 11, 2023 | NetBSD 11.0