'\" t
.\" Copyright, the authors of the Linux man-pages project
.\"
.\" SPDX-License-Identifier: Linux-man-pages-copyleft
.\"
.TH stpcpy 3 2026-03-03 "Linux man-pages 6.18"
.SH NAME
stpcpy \- string return-offset-pointer copy
.SH LIBRARY
Standard C library
.RI ( libc ,\~ \-lc )
.SH SYNOPSIS
.nf
.B #include <string.h>
.P
.BI "char *stpcpy(char *restrict " dst ", const char *restrict " src );
.fi
.P
.RS -4
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.RE
.P
.BR stpcpy ():
.nf
    Since glibc 2.10:
        _POSIX_C_SOURCE >= 200809L
    Before glibc 2.10:
        _GNU_SOURCE
.fi
.SH DESCRIPTION
.BR stpcpy ()
is similar to
.BR strcpy (3),
but returns a pointer to the terminating null byte in
.IR dst .
.P
It is equivalent to both of the following expressions:
.P
.in +4n
.EX
memset(mempcpy(dst, src, strlen(src)), \[aq]\[rs]0\[aq], 1);
strcpy(dst, src) + strlen(src)
.EE
.in
.SH RETURN VALUE
This function returns
a pointer to the terminating null byte of the copied string.
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lbx lb lb
l l l.
Interface	Attribute	Value
T{
.na
.nh
.BR stpcpy ()
T}	Thread safety	MT-Safe
.TE
.SH STANDARDS
POSIX.1-2008.
.SH HISTORY
POSIX.1-2008.
.SH EXAMPLES
.\" SRC BEGIN (stpcpy.c)
.EX
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
\&
int
main(void)
{
    char    *p;
    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()");
\&
    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);
\&
    exit(EXIT_SUCCESS);
}
.EE
.\" SRC END
.SH SEE ALSO
.BR strcpy (3),
.BR strdup (3),
.BR string (3),
.BR wcpcpy (3),
.BR string_copying (7)