strstr, wcsstr, _mbsstr, _mbsstr_l
Returns a pointer to the first occurrence of a search string in a string.
Important
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_mbsstr and _mbsstr_l cannot be used in applications that execute in the Windows Runtime. For more information, see CRT functions not supported with /ZW. |
char *strstr( const char *str, const char *strSearch ); // C only char *strstr( char *str, const char *strSearch ); // C++ only const char *strstr( const char *str, const char *strSearch ); // C++ only wchar_t *wcsstr( const wchar_t *str, const wchar_t *strSearch ); // C only wchar_t *wcsstr( wchar_t *str, const wchar_t *strSearch ); // C++ only const wchar_t *wcsstr( const wchar_t *str, const wchar_t *strSearch ); // C++ only unsigned char *_mbsstr( const unsigned char *str, const unsigned char *strSearch ); // C only unsigned char *_mbsstr( unsigned char *str, const unsigned char *strSearch ); // C++ only const unsigned char *_mbsstr( const unsigned char *str, const unsigned char *strSearch ); // C++ only unsigned char *_mbsstr_l( const unsigned char *str, const unsigned char *strSearch, _locale_t locale ); // C only unsigned char *_mbsstr_l( unsigned char *str, const unsigned char *strSearch, _locale_t locale ); // C++ only const unsigned char *_mbsstr_l( const unsigned char *str, const unsigned char *strSearch, _locale_t locale ); // C++ only
The strstr function returns a pointer to the first occurrence of strSearch in str. The search does not include terminating null characters. wcsstr is the wide-character version of strstr and _mbsstr is the multibyte-character version. The arguments and return value of wcsstr are wide-character strings; those of _mbsstr are multibyte-character strings. _mbsstr validates its parameters. If str or strSearch is NULL, the invalid parameter handler is invoked, as described in Parameter Validation . If execution is allowed to continue, _mbsstr sets errno to EINVAL and returns 0. strstr and wcsstr do not validate their parameters. These three functions behave identically otherwise.
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Security Note
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These functions might incur a threat from a buffer overrun problem. Buffer overrun problems can be used to attack a system because they can allow the execution of arbitrary code, which can cause an unwarranted elevation of privilege. For more information, see Avoiding Buffer Overruns. |
In C, these functions take a const pointer for the first argument. In C++, two overloads are available. The overload that takes a pointer to const returns a pointer to const; the version that takes a pointer to non-const returns a pointer to non-const. The macro _CONST_CORRECT_OVERLOADS is defined if both the const and non-const versions of these functions are available. If you require the non-const behavior for both C++ overloads, define the symbol _CONST_RETURN.
The output value is affected by the locale-category setting of LC_CTYPE; for more information, see setlocale, _wsetlocale. The versions of these functions that do not have the _l suffix use the current locale for this locale-dependent behavior; the versions that have the _l suffix are identical except that they instead use the locale parameter that's passed in. For more information, see Locale.
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TCHAR.H routine |
_UNICODE & _MBCS not defined |
_MBCS defined |
_UNICODE defined |
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_tcsstr |
strstr |
_mbsstr |
wcsstr |
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n/a |
n/a |
_mbsstr_l |
n/a |
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Routine |
Required header |
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strstr |
<string.h> |
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wcsstr |
<string.h> or <wchar.h> |
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_mbsstr , _mbsstr_l |
<mbstring.h> |
For more information about compatibility, see Compatibility.
// crt_strstr.c
#include <string.h>
#include <stdio.h>
char str[] = "lazy";
char string[] = "The quick brown dog jumps over the lazy fox";
char fmt1[] = " 1 2 3 4 5";
char fmt2[] = "12345678901234567890123456789012345678901234567890";
int main( void )
{
char *pdest;
int result;
printf( "String to be searched:\n %s\n", string );
printf( " %s\n %s\n\n", fmt1, fmt2 );
pdest = strstr( string, str );
result = (int)(pdest - string + 1);
if ( pdest != NULL )
printf( "%s found at position %d\n", str, result );
else
printf( "%s not found\n", str );
}
String to be searched:
The quick brown dog jumps over the lazy fox
1 2 3 4 5
12345678901234567890123456789012345678901234567890
lazy found at position 36