memmove
Moves one buffer to another.
void*memmove(void*dest,constvoid*src,size_tcount**);**
| Routine | Required Header | Compatibility |
| memmove | <string.h> | ANSI, Win 95, Win NT |
For additional compatibility information, see Compatibility in the Introduction.
Libraries
| LIBC.LIB | Single thread static library, retail version |
| LIBCMT.LIB | Multithread static library, retail version |
| MSVCRT.LIB | Import library for MSVCRT.DLL, retail version |
Return Value
memmove returns the value of dest.
Parameters
dest
Destination object
src
Source object
count
Number of bytes of characters to copy
Remarks
The memmove function copies count bytes of characters from src to dest. If some regions of the source area and the destination overlap, memmove ensures that the original source bytes in the overlapping region are copied before being overwritten.
Example
/* MEMCPY.C: Illustrate overlapping copy: memmove
* handles it correctly; memcpy does not.
*/
#include <memory.h>
#include <string.h>
#include <stdio.h>
char string1[60] = "The quick brown dog jumps over the lazy fox";
char string2[60] = "The quick brown fox jumps over the lazy dog";
/* 1 2 3 4 5
* 12345678901234567890123456789012345678901234567890
*/
void main( void )
{
printf( "Function:\tmemcpy without overlap\n" );
printf( "Source:\t\t%s\n", string1 + 40 );
printf( "Destination:\t%s\n", string1 + 16 );
memcpy( string1 + 16, string1 + 40, 3 );
printf( "Result:\t\t%s\n", string1 );
printf( "Length:\t\t%d characters\n\n", strlen( string1 ) );
/* Restore string1 to original contents */
memcpy( string1 + 16, string2 + 40, 3 );
printf( "Function:\tmemmove with overlap\n" );
printf( "Source:\t\t%s\n", string2 + 4 );
printf( "Destination:\t%s\n", string2 + 10 );
memmove( string2 + 10, string2 + 4, 40 );
printf( "Result:\t\t%s\n", string2 );
printf( "Length:\t\t%d characters\n\n", strlen( string2 ) );
printf( "Function:\tmemcpy with overlap\n" );
printf( "Source:\t\t%s\n", string1 + 4 );
printf( "Destination:\t%s\n", string1 + 10 );
memcpy( string1 + 10, string1 + 4, 40 );
printf( "Result:\t\t%s\n", string1 );
printf( "Length:\t\t%d characters\n\n", strlen( string1 ) );
}
Output
Function: memcpy without overlap
Source: fox
Destination: dog jumps over the lazy fox
Result: The quick brown fox jumps over the lazy fox
Length: 43 characters
Function: memmove with overlap
Source: quick brown fox jumps over the lazy dog
Destination: brown fox jumps over the lazy dog
Result: The quick quick brown fox jumps over the lazy dog
Length: 49 characters
Function: memcpy with overlap
Source: quick brown dog jumps over the lazy fox
Destination: brown dog jumps over the lazy fox
Result: The quick quick brown dog jumps over the lazy fox
Length: 49 characters