CONTROL
- Introduction to CTRL
- CONTROL Classes
- Types of Control Functions
- CONTROL graphics
- CONTROL Functions
  - Funtions A
  - Funtions B
  - Funtions C
  - Funtions D
  - Functions E
  - Functions F
    - fclose()
      Closes a file.
    - folderSelector()
      Opens the folder selector dialog and writes the name of the selected folder to the string variable "path".
    - fileSelector()
      Opens the file selection dialog and writes the selected file name to fileName.
    - fscanfPL()
      Reads a file similar to fscanf() except changes to the current WinCC OA language before converting.
    - floor()
      Rounds down to an integer.
    - findExecutable()
      The function searches for the given executable and returns the full path to it or an empty string if not found.
    - fwrite()
      Writes a number of bytes from a blob variable to a file.
    - fprintfPL()
      Writes to a file similar to fprintf() except changes to the current WinCC OA language before converting.
    - fseek()
      Sets the pointer of the file f from the position whence to the position defined by the offset.
    - formatTimeUTC()
      Returns the UTC time in a particular format.
    - fabs()
      Returns the absolute value of x.
    - fflush()
      Writes data to a file.
    - fprintf()
      Writes to a file.
    - fswAddPath()
      The functions add a path for monitoring to the FileSystemWatcher.
    - formatDebug()
      Similar to the function Debug() but instead of writing to the log viewer returns the debug messages as string,.
    - fmod()
    - formatTime()
      Returns the time in a particular format.
    - fscanf()
      Reads a file.
    - fillSelector()
      Opens the filling pattern selector and writes the selection to a variable.
    - fileToString()
      This function loads an ASCII file and writes the contents into a string variable.
    - fontSelector()
      Opens the font type selector and writes the selection to a variable.
    - fopen()
      Opens a file.
    - feof()
      Examines whether an end of file has been noted.
    - formatSelector()
      Opens the format selector and writes the string format that has been selected on the format string variable.
    - fread()
      Reads a number of bytes from a file to a blob variable.
    - fscanfUL()
      Reads a file like fscanf(), but change to the current Windows user language before converting.
    - fileEditor()
      Opens text files such as .txt and .doc files in an editor. You can edit both plain and rich text.
    - fputs()
      Writes a string to a file.
    - fprintfUL()
      Writes to a file similar to fprintf() except changes to the current Windows user language before converting.
    - fgets()
      Returns a string from a file.
    - ftell()
      The ftell function obtains the current value of the file position indicator for the stream pointed to by f.
    - ferror()
      Examines whether a file error has been noted.
    - fswRemovePath()
      The function removes a path from the monitoring of the FileSystemWatcher.
  - Functions G
  - Functions H
  - Functions I
  - Functions J
  - Functions K
  - Functions L
  - Functions M
  - Functions N
  - Functions O
  - Functions P
  - Functions Q
  - Functions R
  - Functions S
  - Functions T
  - Functions U
  - Functions V
  - Functions W
  - Functions X
  - Functions Y
  - Functions Z
- CTRL Debugger
  With the CTRL Debugger you can debug the programming language Control.

fwrite()

Writes a number of bytes from a blob variable to a file.

Synopsis

int fwrite(file f, blob b, int numBytes);

Parameters


Parameters	Meaning
f	File to which should be written
b	blob variable
numBytes	Number of bytes to be written.

Return value

In the event of errors, the function returns -1 or EOF otherwise, the number of written characters.

Description

Writes a number of bytes from a blob variable to a file.

Example

Writes 4 bytes and reads 2 bytes to/from a file.

main()
{
  blob target, rtarget;
  int len, pos;
  string s;
  anytype value;
  bool bigendian;
  s = "FFAB003AFF";
  target = s;
  DebugN(target);
  len = 1;
  value = 5;
  bigendian = TRUE;
  DebugN("Blob AppendValue: " + blobAppendValue(target, value, len, bigendian)); //blob length is 6 = FF AB0 3A FF 5
  DebugN(target); //ff ab 0 3a ff 5
  int fr, fw, numW, fcl, err, numR;
  file wf;
  wf = fopen("D:\\BFile.txt", "w");
  numR = 2;
  numW = 4;
  err = ferror(wf);
  fw = fwrite(wf, target, numW);
  DebugN("Number of bytes that could be written:", fw);
  //Output: ["Number of bytes that could be written:"][4]
  fr = fread(wf, rtarget, numR);
  DebugN("Number of bytes that could be read:", fr);
  //Output: ["Number of bytes that could be read:"][2]
  fcl = fclose(wf);
}

Assignment

File functions

Availability

CTRL