NAME

       stpcpy, strcpy, strcat - copy or catenate a string

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

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       stpcpy():
           Since glibc 2.10:
               _POSIX_C_SOURCE >= 200809L
           Before glibc 2.10:
               _GNU_SOURCE

DESCRIPTION

       stpcpy()
       strcpy()
              These  functions  copy  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.  For the difference between the two
              functions, see RETURN VALUE.

       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.

       An implementation of these functions might be:

           char *
           stpcpy(char *restrict dst, const char *restrict src)
           {
               char  *p;

               p = mempcpy(dst, src, strlen(src));
               *p = '\0';

               return p;
           }

           char *
           strcpy(char *restrict dst, const char *restrict src)
           {
               stpcpy(dst, src);
               return dst;
           }

           char *
           strcat(char *restrict dst, const char *restrict src)
           {
               stpcpy(dst + strlen(dst), src);
               return dst;
           }

RETURN VALUE

       stpcpy()
              This function returns a pointer to the terminating null byte of the copied string.

       strcpy()
       strcat()
              These functions return dst.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       ┌───────────────────────────────────────────────────────────────┬───────────────┬─────────┐
       │Interface                                                      │ Attribute     │ Value   │
       ├───────────────────────────────────────────────────────────────┼───────────────┼─────────┤
       │stpcpy(), strcpy(), strcat()                                   │ Thread safety │ MT-Safe │
       └───────────────────────────────────────────────────────────────┴───────────────┴─────────┘

STANDARDS

       stpcpy()
              POSIX.1-2008.

       strcpy()
       strcat()
              POSIX.1-2001, POSIX.1-2008, C99, 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).

       strcat()    can    be    very    inefficient.     Read    about    Shlemiel    the painter
       ⟨https://www.joelonsoftware.com/2001/12/11/back-to-basics/⟩.

EXAMPLES

       #include <err.h>
       #include <stdio.h>
       #include <stdlib.h>
       #include <string.h>

       int
       main(void)
       {
           char    *p;
           char    *buf1;
           char    *buf2;
           size_t  len, maxsize;

           maxsize = strlen("Hello ") + strlen("world") + strlen("!") + 1;
           buf1 = malloc(sizeof(*buf1) * maxsize);
           if (buf1 == NULL)
               err(EXIT_FAILURE, "malloc()");
           buf2 = malloc(sizeof(*buf2) * maxsize);
           if (buf2 == NULL)
               err(EXIT_FAILURE, "malloc()");

           p = buf1;
           p = stpcpy(p, "Hello ");
           p = stpcpy(p, "world");
           p = stpcpy(p, "!");
           len = p - buf1;

           printf("[len = %zu]: ", len);
           puts(buf1);  // "Hello world!"
           free(buf1);

           strcpy(buf2, "Hello ");
           strcat(buf2, "world");
           strcat(buf2, "!");
           len = strlen(buf2);

           printf("[len = %zu]: ", len);
           puts(buf2);  // "Hello world!"
           free(buf2);

           exit(EXIT_SUCCESS);
       }

SEE ALSO

       strdup(3), string(3), wcscpy(3), string_copying(7)