_strdup
, _wcsdup
, _mbsdup
Duplicates strings.
Important
_mbsdup
cannot be used in applications that execute in the Windows Runtime. For more information, see CRT functions not supported in Universal Windows Platform apps.
Syntax
char *_strdup(
const char *strSource
);
wchar_t *_wcsdup(
const wchar_t *strSource
);
unsigned char *_mbsdup(
const unsigned char *strSource
);
Parameters
strSource
Null-terminated source string.
Return value
Each of these functions returns a pointer to the storage location for the copied string or NULL
if storage can't be allocated.
Remarks
The _strdup
function calls malloc
to allocate storage space for a copy of strSource
and then copies strSource
to the allocated space.
_wcsdup
and _mbsdup
are wide-character and multibyte-character versions of _strdup
. The arguments and return value of _wcsdup
are wide-character strings. The arguments and return value of _mbsdup
are multibyte-character strings. These three functions behave identically otherwise.
By default, this function's global state is scoped to the application. To change this behavior, see Global state in the CRT.
Generic-text routine mappings
TCHAR.H routine |
_UNICODE and _MBCS not defined |
_MBCS defined |
_UNICODE defined |
---|---|---|---|
_tcsdup |
_strdup |
_mbsdup |
_wcsdup |
Because _strdup
calls malloc
to allocate storage space for the copy of strSource
, it's good practice always to release this memory by calling the free
routine on the pointer that's returned by the call to _strdup
.
If _DEBUG
and _CRTDBG_MAP_ALLOC
are defined, _strdup
and _wcsdup
are replaced by calls to _strdup_dbg
and _wcsdup_dbg
, to allow for debugging memory allocations. For more information, see _strdup_dbg
, _wcsdup_dbg
.
Requirements
Routine | Required header |
---|---|
_strdup |
<string.h> |
_wcsdup |
<string.h> or <wchar.h> |
_mbsdup |
<mbstring.h> |
For more compatibility information, see Compatibility.
Example
// crt_strdup.c
#include <string.h>
#include <stdio.h>
int main( void )
{
char buffer[] = "This is the buffer text";
char *newstring;
printf( "Original: %s\n", buffer );
newstring = _strdup( buffer );
printf( "Copy: %s\n", newstring );
free( newstring );
}
Original: This is the buffer text
Copy: This is the buffer text
See also
String manipulation
memset
, wmemset
strcat
, wcscat
, _mbscat
strcmp
, wcscmp
, _mbscmp
strncat
, _strncat_l
, wcsncat
, _wcsncat_l
, _mbsncat
, _mbsncat_l
strncmp
, wcsncmp
, _mbsncmp
, _mbsncmp_l
strncpy
, _strncpy_l
, wcsncpy
, _wcsncpy_l
, _mbsncpy
, _mbsncpy_l
_strnicmp
, _wcsnicmp
, _mbsnicmp
, _strnicmp_l
, _wcsnicmp_l
, _mbsnicmp_l
strrchr
, wcsrchr
, _mbsrchr
, _mbsrchr_l
strspn
, wcsspn
, _mbsspn
, _mbsspn_l
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