wmemcpy, wmemcpy_s
From cppreference.com
Defined in header
<wchar.h>
|
||
(1) | ||
wchar_t
*
wmemcpy
(
wchar_t
*
dest,
const
wchar_t
*
src,
size_t
count
)
;
|
(since C95)
(until C99) |
|
wchar_t
*
wmemcpy
(
wchar_t
*
restrict
dest,
const
wchar_t
*
restrict
src,
size_t count ) ; |
(since C99) | |
errno_t wmemcpy_s
(
wchar_t
*
restrict
dest, rsize_t destsz,
const wchar_t * restrict src, rsize_t count ) ; |
(2) | (since C11) |
1)
Copies exactly
count
successive wide characters from the wide character array pointed to by
src
to the wide character array pointed to by
dest
. If the objects overlap, the behavior is undefined. If
count
is zero, the function does nothing.
2)
Same as
(1)
, except that the following errors are detected at runtime and call the currently installed
constraint handler
function:
-
-
src
ordest
is a null pointer -
destsz
orcount
is greater than RSIZE_MAX / sizeof ( wchar_t ) -
count
is greater thandestsz
(overflow would occur) - overlap would occur between the source and the destination arrays
-
-
As with all bounds-checked functions,
wmemcpy_s
is only guaranteed to be available if __STDC_LIB_EXT1__ is defined by the implementation and if the user defines __STDC_WANT_LIB_EXT1__ to the integer constant 1 before including <wchar.h> .
Parameters
dest | - | pointer to the wide character array to copy to |
src | - | pointer to the wide character array to copy from |
count | - | number of wide characters to copy |
destsz | - | max number of wide characters to write (the size of the destination buffer) |
Return value
1)
returns a copy of
dest
2)
returns zero on success, returns non-zero on error. Also, on error, fills the entire
dst
up to and not including
dst
+
dstsz
with null wide characters,
L
'
\0
'
(unless
dest
is null or
destsz
is greater than
RSIZE_MAX
/
sizeof
(
wchar_t
)
)
Notes
This function's analog for byte strings is strncpy , not strcpy .
This function is not locale-sensitive and pays no attention to the values of the wchar_t objects it copies: nulls as well as invalid characters are copied too.
Example
Run this code
#include <stdio.h> #include <wchar.h> #include <locale.h> int main(void) { wchar_t from1[] = L"नमस्ते"; size_t sz1 = sizeof from1 / sizeof *from1; wchar_t from2[] = L"Բարև"; size_t sz2 = sizeof from2 / sizeof *from2; wchar_t to[sz1 + sz2]; wmemcpy(to, from1, sz1); // copy from1, along with its null terminator wmemcpy(to + sz1, from2, sz2); // append from2, along with its null terminator setlocale(LC_ALL, "en_US.utf8"); printf("Wide array contains: "); for(size_t n = 0; n < sizeof to / sizeof *to; ++n) if(to[n]) printf("%lc", to[n]); else printf("\\0"); printf("\n"); }
Possible output:
Wide array contains: नमस्ते\0Բարև\0
References
- C11 standard (ISO/IEC 9899:2011):
-
- 7.29.4.2.3 The wmemcpy function (p: 431)
-
- K.3.9.2.1.3 The wmemcpy_s function (p: 641)
- C99 standard (ISO/IEC 9899:1999):
-
- 7.24.4.2.3 The wmemcpy function (p: 377)
See also
(C95)
(C11)
|
copies a certain amount of wide characters between two, possibly overlapping, arrays
(function) |
(C11)
|
copies a certain amount of characters from one string to another
(function) |
C++ documentation
for
wmemcpy
|