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uphp:functions:fread

fread

WMPRO, WMMINI FW >= 1.0 WMMEGA FW >= 2.0

Read bytes from a file, stream or socket

Description

mixed fread ( int $handle, int $bytes )

This function attempts to read a specified number of bytes from a file, stream or socket. If less than the number of bytes are available it will return the available data. If no data is available it will return an empty string.

Parameters

$handle: Valid handle of a previously opened resource

$bytes: Limit to the number of bytes returned

Return Values

  • String containing the data requested from the resource
    • The length of the returned string depends on available data (0 to $bytes)
  • Integer 0 for error

Example

Read the 32 byte MD5 hash from file /md5.txt

<?
  $fp=fopen("/md5.txt","r");
  if ($fp) {
    $data=fread($fp,32); // read 32 bytes from the file
    print($data);
    fclose($fp);
  } else {
    print("File open failed\n");
  }
?>

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

fgets() - Return a single line from a file, stream or socket, with optional size limit

fwrite() - Write data to a file, stream or socket

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

uphp/functions/fread.txt · Last modified: 2021/09/13 05:57 (external edit)