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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).

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

STANDARDS

       stpcpy()
              POSIX.1-2008.

       strcpy()
       strcat()
              C11, POSIX.1-2008.

STANDARDS

       stpcpy()
              POSIX.1-2008.

       strcpy()
       strcat()
              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).

       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)