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strcat, wcscat, _mbscat

Append a string.

char *strcat(
   char *strDestination,
   const char *strSource 
wchar_t *wcscat(
   wchar_t *strDestination,
   const wchar_t *strSource 
unsigned char *_mbscat(
   unsigned char *strDestination,
   const unsigned char *strSource 


Null-terminated destination string.
Null-terminated source string.

Return Value

Each of these functions returns the destination string (strDestination). No return value is reserved to indicate an error.


The strcat function appends strSource to strDestination and terminates the resulting string with a null character. The initial character of strSource overwrites the terminating null character of strDestination. The behavior of strcat is undefined if the source and destination strings overlap.

Security Note   Because strcat does not check for sufficient space in strDestination before appending strSource, it is a potential cause of buffer overruns. Consider using strncat instead.

wcscat and _mbscat are wide-character and multibyte-character versions of strcat. The arguments and return value of wcscat are wide-character strings; those of _mbscat 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
_tcscat strcat _mbscat wcscat


Routine Required header Compatibility
strcat <string.h> ANSI, Win 98, Win Me, Win NT, Win 2000, Win XP
wcscat <string.h> or <wchar.h> ANSI, Win 98, Win Me, Win NT, Win 2000, Win XP
_mbscat <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.


See the example for strcpy.

See Also

String Manipulation Routines | strncat | strncmp | strncpy | _strnicmp | strrchr | strspn | Run-Time Routines and .NET Framework Equivalents