wmemcpy, wmemcpy_s
From cppreference.com
Defined in header <wchar.h>
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(1) | ||
wchar_t
* wmemcpy(
wchar_t
* dest, const
wchar_t
* src, size_t count )
;
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(since C95) (until C99) |
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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
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
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)
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copies a certain amount of wide characters between two, possibly overlapping, arrays (function) |
(C11)
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copies a certain amount of characters from one string to another (function) |
C++ documentation for wmemcpy
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