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_strdup, _wcsdup, _mbsdup

Duplicate strings.

char *_strdup(
   const char *strSource 
wchar_t *_wcsdup(
   const wchar_t *strSource 
unsigned char *_mbsdup(
   const unsigned char *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 cannot be allocated.


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; those of _mbsdup are multibyte-character strings. These three functions behave identically otherwise.

Generic-Text Routine Mappings

TCHAR.H routine _UNICODE & _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 is good practice always to release this memory by calling the free routine on the pointer returned by the call to _strdup.


Routine Required header Compatibility
_strdup <string.h> Win 98, Win Me, Win NT, Win 2000, Win XP
_wcsdup <string.h> or <wchar.h> Win 98, Win Me, Win NT, Win 2000, Win XP
_mbsdup <mbstring.h> Win 98, Win Me, Win NT, Win 2000, Win XP

For additional compatibility information, see Compatibility in the Introduction.


All versions of the C run-time libraries.


// 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 Routines | memset | strcat | strcmp | strncat | strncmp | strncpy | _strnicmp | strrchr | strspn | Run-Time Routines and .NET Framework Equivalents