strcpy (3p) - Linux Manuals

strcpy: copy a string


This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.


strcpy - copy a string


#include <string.h>

char *strcpy(char *restrict s1, const char *restrict s2);


The strcpy() function shall copy the string pointed to by s2 (including the terminating null byte) into the array pointed to by s1. If copying takes place between objects that overlap, the behavior is undefined.


The strcpy() function shall return s1; no return value is reserved to indicate an error.


No errors are defined.

The following sections are informative.


Initializing a String

The following example copies the string "----------" into the permstring variable.

#include <string.h>
static char permstring[11];
strcpy(permstring, "----------");

Storing a Key and Data

The following example allocates space for a key using malloc() then uses strcpy() to place the key there. Then it allocates space for data using malloc(), and uses strcpy() to place data there. (The user-defined function dbfree() frees memory previously allocated to an array of type struct element *.)

#include <string.h>
#include <stdlib.h>
#include <stdio.h>
/* Structure used to read data and store it. */
struct element {
    char *key;
    char *data;

struct element *tbl, *curtbl;
char *key, *data;
int count;
void dbfree(struct element *, int);
if ((curtbl->key = malloc(strlen(key) + 1)) == NULL) {
    perror("malloc"); dbfree(tbl, count); return NULL;
strcpy(curtbl->key, key);

if ((curtbl->data = malloc(strlen(data) + 1)) == NULL) {
    perror("malloc"); free(curtbl->key); dbfree(tbl, count); return NULL;
strcpy(curtbl->data, data);


Character movement is performed differently in different implementations. Thus, overlapping moves may yield surprises.

This issue is aligned with the ISO C standard; this does not affect compatibility with XPG3 applications. Reliable error detection by this function was never guaranteed.






Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at .


strncpy(), the Base Definitions volume of IEEE Std 1003.1-2001, <string.h>