wmemmove, wmemmove_s

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< c ‎ | string ‎ | wide
C
Strings library
Null-terminated wide strings
Functions
Character manipulation
Conversions to numeric formats
(C95) (C99)
(C95) (C99)
String manipulation
Array manipulation
(C95) (C11)
wmemmove wmemmove_s
(C95) (C11)
Defined in header <wchar.h>
wchar_t * wmemmove ( wchar_t * dest, const wchar_t * src, size_t count ) ;
(1) (since C95)
errno_t wmemmove_s ( wchar_t * dest, rsize_t destsz,
const wchar_t * 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 count is zero, the function does nothing. The arrays may overlap: copying takes place as if the wide characters were copied to a temporary wide character array and then copied from the temporary array to dest .
2) Same as (1) , except that the following errors are detected at runtime and call the currently installed constraint handler function:
  • src or dest is a null pointer
  • destsz or count is greater than RSIZE_MAX / sizeof ( wchar_t )
  • count is greater than destsz (overflow would occur)
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
destsz - max number of wide characters to write (the size of the destination buffer)
count - number of wide characters to copy

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 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 <locale.h>
#include <stdio.h>
#include <wchar.h>
 
int main(void)
{
    setlocale(LC_ALL, "en_US.utf8");
 
    wchar_t str[] = L"αβγδεζηθικλμνξοπρστυφχψω";
    printf("%ls\n", str);
    wmemmove(str + 4, str + 3, 3); // copy from [δεζ] to [εζη]
    printf("%ls\n", str);
}

Output: 

αβγδεζηθικλμνξοπρστυφχψω
αβγδδεζθικλμνξοπρστυφχψω

References

  • C23 standard (ISO/IEC 9899:2024):
  • 7.29.4.2.4 The wmemmove function (p: TBD)
  • K.3.9.2.1.4 The wmemmove_s function (p: TBD)
  • C17 standard (ISO/IEC 9899:2018):
  • 7.29.4.2.4 The wmemmove function (p: TBD)
  • K.3.9.2.1.4 The wmemmove_s function (p: TBD)
  • C11 standard (ISO/IEC 9899:2011):
  • 7.29.4.2.4 The wmemmove function (p: 432)
  • K.3.9.2.1.4 The wmemmove_s function (p: 642)
  • C99 standard (ISO/IEC 9899:1999):
  • 7.24.4.2.4 The wmemmove function (p: 378)

See also

(C11)
moves one buffer to another
(function)
(C95) (C11)
copies a certain amount of wide characters between two non-overlapping arrays
(function)
C++ documentation for wmemmove
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