strcat, wcscat, _mbscat

Article
12/21/2012

Append a string. More secure versions of these functions are available; see strcat_s, wcscat_s, _mbscat_s.

Important

_mbscat_s cannot be used in applications that execute in the Windows Runtime. For more information, see CRT functions not supported with /ZW.

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 
);
template <size_t size>
char *strcat(
   char (&strDestination)[size],
   const char *strSource 
); // C++ only
template <size_t size>
wchar_t *wcscat(
   wchar_t (&strDestination)[size],
   const wchar_t *strSource 
); // C++ only
template <size_t size>
unsigned char *_mbscat(
   unsigned char (&strDestination)[size],
   const unsigned char *strSource 
); // C++ only

Parameters

strDestination
Null-terminated destination string.
strSource
Null-terminated source string.

Return Value

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

Remarks

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.

In C++, these functions have template overloads that invoke the newer, secure counterparts of these functions. For more information, see Secure Template Overloads.

Generic-Text Routine Mappings

TCHAR.H routine	_UNICODE & _MBCS not defined	_MBCS defined	_UNICODE defined
_tcscat	strcat	_mbscat	wcscat

Requirements

Routine	Required header
strcat	<string.h>
wcscat	<string.h> or <wchar.h>
_mbscat	<mbstring.h>

For additional compatibility information, see Compatibility in the Introduction.

Example

See the example for strcpy.

.NET Framework Equivalent

System::String::Concat

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