---
name: "strcpy"
section: "3"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "freebsd", "macos"]
url: "https://new.carta.tech/strcpy"
---

# strcpy(3)

string copy/catenate

## NAME

strcpy, strcat - string copy/catenate

## LIBRARY

Standard C library (*libc*, *-lc*)

## SYNOPSIS

```
#include <string.h>
```

**char \*strcpy(char \*restrict** *dst***, const char \*restrict** *src***);** **char \*strcat(char \*restrict** *dst***, const char \*restrict** *src***);**

## DESCRIPTION

- **strcpy**()

  This function copies the string pointed to by *src*, into a string at the buffer pointed to by *dst*. The programmer is responsible for allocating a destination buffer large enough, that is, *strlen(src) + 1*.

-

  It is equivalent to

-

  ```
  stpcpy(dst, src), dst
  ```

- **strcat**()

  This function catenates the string pointed to by *src*, after the string pointed to by *dst* (overwriting its terminating null byte). The programmer is responsible for allocating a destination buffer large enough, that is, *strlen(dst) + strlen(src) + 1*.

-

  It is equivalent to

-

  ```
  stpcpy(strnul(dst), src), dst
  ```

## RETURN VALUE

These functions return *dst*.

## ATTRIBUTES

For an explanation of the terms used in this section, see [**attributes**(7)](/attributes/7.md).

| | | |
| --- | --- | --- |
| **Interface** | **Attribute** | **Value** |
| **strcpy**(), **strcat**() | Thread safety | MT-Safe |

## STANDARDS

C11, POSIX.1-2008.

## HISTORY

POSIX.1-2001, C89, SVr4, 4.3BSD.

## CAVEATS

The strings *src* and *dst* may not overlap.

If the destination buffer is not large enough, the behavior is undefined. See **\_FORTIFY\_SOURCE** in [**feature\_test\_macros**(7)](/feature_test_macros/7.md).

## EXAMPLES

```
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int
main(void)
{
    char    *buf1;
    size_t  len, size;
    size = strlen("Hello ") + strlen("world") + strlen("!") + 1;
    buf1 = malloc(sizeof(*buf1) * size);
    if (buf1 == NULL)
        err(EXIT_FAILURE, "malloc()");
    strcpy(buf1, "Hello ");
    strcat(buf1, "world");
    strcat(buf1, "!");
    len = strlen(buf1);
    printf("[len = %zu]: ", len);
    puts(buf1);  // "Hello world!"
    free(buf1);
    exit(EXIT_SUCCESS);
}
```

## SEE ALSO

[**stpcpy**(3)](/stpcpy/3.md), [**strdup**(3)](/strdup/3.md), [**string**(3)](/string/3.md), [**wcscpy**(3)](/wcscpy/3.md), [**string\_copying**(7)](/string_copying/7.md)