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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ATTRIBUTES | STANDARDS | STANDARDS | CAVEATS | EXAMPLES | SEE ALSO | COLOPHON |
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strcpy(3) Library Functions Manual strcpy(3)
stpcpy, strcpy, strcat - copy or catenate a string
Standard C library (libc, -lc)
#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
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;
}
stpcpy()
This function returns a pointer to the terminating null
byte of the copied string.
strcpy()
strcat()
These functions return dst.
For an explanation of the terms used in this section, see
attributes(7).
┌─────────────────────────────────────┬───────────────┬─────────┐
│ Interface │ Attribute │ Value │
├─────────────────────────────────────┼───────────────┼─────────┤
│ stpcpy(), strcpy(), strcat() │ Thread safety │ MT-Safe │
└─────────────────────────────────────┴───────────────┴─────────┘
stpcpy()
POSIX.1-2008.
strcpy()
strcat()
C11, POSIX.1-2008.
stpcpy()
POSIX.1-2008.
strcpy()
strcat()
POSIX.1-2001, C89, SVr4, 4.3BSD.
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/⟩.
#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);
}
strdup(3), string(3), wcscpy(3), string_copying(7)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.9.1.tar.gz
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⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2024-06-26. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
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part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.9.1 2024-06-15 strcpy(3)
Pages that refer to this page: bcopy(3), memccpy(3), memcpy(3), memmove(3), string(3), wcpcpy(3), wcscat(3), wcscpy(3), feature_test_macros(7), signal-safety(7), string_copying(7)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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