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memchr, wmemchr

Visual Studio 2005

Find characters in a buffer.


void *memchr(
   const void *buf,
   int c,
   size_t count
); // C only
void *memchr(
   void *buf,
   int c,
   size_t count
); // C++ only
const void *memchr(
   const void *buf,
   int c,
   size_t count
); // C++ only
wchar_t *wmemchr(
   const wchar_t * buf, 
   wchar_t c,
   size_t count
); // C only
wchar_t *wmemchr(
   wchar_t * buf, 
   wchar_t c,
   size_t count
); // C++ only
const wchar_t *wmemchr(
   const wchar_t * buf, 
   wchar_t c,
   size_t count
); // C++ only

Parameters

buf: Pointer to buffer.

c: Character to look for.

count: Number of characters to check.

Return Value

If successful, returns a pointer to the first location of c in buf. Otherwise it returns NULL.

Remarks

memchr and wmemchr look for the first occurrence of c in the first count bytes of buf. It stops when it finds c or when it has checked the first count bytes.

In C, these functions take a const pointer for the first argument. In C++, two overloads are available. The overload taking 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++ overloadsin C++, define the symbol _CONST_RETURN.

Requirements

Routine	Required header	Compatibility
memchr	<memory.h> or <string.h>	ANSI, Windows 95, Windows 98, Windows 98 Second Edition, Windows Millennium Edition, Windows Millennium Edition, Windows NT 4.0, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003
wmemchr	<wchar.h>	ANSI, Windows 95, Windows 98, Windows 98 Second Edition, Windows Millennium Edition, Windows Millennium Edition, Windows NT 4.0, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003

For more information about compatibility, see Compatibility.

Libraries

All versions of the C run-time libraries.

Example

// crt_memchr.c

#include <memory.h>
#include <stdio.h>

int  ch = 'r';
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 );

   printf( "Search char: %c\n", ch );
   pdest = memchr( string, ch, sizeof( string ) );
   result = (int)(pdest - string + 1);
   if ( pdest != NULL )
      printf( "Result:      %c found at position %d\n", ch, result );
   else
      printf( "Result:      %c not found\n" );
}

Output

String to be searched:
             The quick brown dog jumps over the lazy fox
                      1         2         3         4         5
             12345678901234567890123456789012345678901234567890

Search char: r
Result:      r found at position 12

.NET Framework Equivalent

Not applicable. To call the standard C function, use PInvoke. For more information, see Platform Invoke Examples.

Reference

Buffer Manipulation
_memccpy
memcmp, wmemcmp
memcpy, wmemcpy
memset, wmemset
strchr, wcschr, _mbschr, _mbschr_l

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