======fwrite====== WMPRO, WMMINI FW >= 1.0 WMMEGA FW >= 2.0 Write data to a file, stream or socket ====Description==== int fwrite ( int $handle, mixed $data [, int $length] ) This function performs a binary-safe write of strings or bytes specified by integers to a previously opened resource((This function is similar to the mainline PHP function, but with the addition of the ability to write bytes specified as an integer, and the ability to write string or integer data from an array. Both of these capabilities simplify programming in uPHP for the [[hardware:wattmons|Wattmon]]: data to be written can be specified as an int byte value instead of a string, or a series of writes of either type can be combined into one statement by the use of an array.)) ====Parameters==== $handle: Valid handle of a previously opened resource $data: The string, int or array data to be written in one of the following forms: * string - A string to write * int - A single byte to write specified as an integer (8 bits, decimal 0-255)((If the data is type int then 1 byte will be written to the resource, even if the integer is not in the range 0 to 255 (for which there may be unexpected results). For example, integer '321' is equivalent to writing '65' which will write the character 'A' to the resource (321 modulo 256 = 65). If the data is type float then 0 bytes will be written.)) * array - A series of string and/or int byte data to write - useful for writing several strings and/or binary data to a resource((If the data is type array and the array contains integers that are not in the range from 0 to 255 (8 bits) then multiple bytes will be written (up to 4 bytes or 32 bits, which may be unexpected). Array elements that are type float or array will always write 0 bytes.)) $length: Optional length of buffer - automatically calculated for strings if not specified ====Return Values==== Integer **number of bytes successfully written** **0** if no bytes were written((A return value of 0 can happen for an invalid handle, an empty string, or if the data is type float.)) **-1** for socket errors (reset, connection broken)((FW < 1.1019 returned **0** for socket errors.)) ====Examples====

The above example will display:


24 bytes were written to the file

And the above example will create the file /fwrite_test.txt containing:


Line 1
ABCDEF
Line 3

====Note==== When working with binary data such as data read from a file using fread(), make sure to pass the variable as a pointer using the & symbol. Otherwise a copy of the string will be made but will only be copied until the first NULL character is found. For example, this script will make an exact copy of the contents of file original.bin into copy.bin:


512) {
       $buflen=512;
     } else $buflen=$len;
     $data = fread($fo,512);
     // make sure you also specify the optional file size 
     // or else it will use the length of the string (till the first null).
     // also, pass the variable by reference
     fwrite($fh,&$data,512);
     $len = $len - $buflen;
  }
  fclose($fh);
  fclose($fo);
?>

====See Also==== [[fopen()]] - Open a file for reading or writing [[fseropen()]] - Open the serial port at the specified baud rate with optional parameters [[f485open()]] - Open the RS-485 port at the specified baud rate and parity [[fsockopen()]] - Open an internet socket connection with optional timeout [[fread()]] - Read bytes from a file, stream or socket [[fgets()]] - Return a single line from a file, stream or socket, with optional size limit [[feof()]] - Test if no more data is available in a file, stream or socket [[filesize()]] - Return the size of a file, or the number of unread bytes in a stream or socket [[fseek()]] - Position the file pointer in an open file [[ftell()]] - Return the current position of a file read/write pointer [[fclose()]] - Close a file, stream or socket