64bit実行ファイルかどうか

is64.cpp

#include <windows.h>
#include <stdio.h>

int main( int argc, char **argv )
{
	if( argc < 2 )
		return -1;

	FILE *fp = fopen( argv[1], "rb" );
	if( fp==NULL )
		return -1;
	IMAGE_DOS_HEADER idh;
	if( fread( &idh, sizeof(idh), 1, fp ) != 1 )
		return -1;
	if( idh.e_magic != 0x5a4d )
		return -1;
	fseek( fp, idh.e_lfanew, SEEK_SET );
	IMAGE_NT_HEADERS inh;
	if( fread( &inh, sizeof(inh), 1, fp ) != 1 )
		return -1;
	fclose( fp );

	return inh.FileHeader.Machine == IMAGE_FILE_MACHINE_AMD64;
}