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 returns the selected file name.
    - 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.
- CtrlExtension, basics

fseek()

Sets the pointer of the file f from the position whence to the position defined by the offset.

Synopsis

int fseek(file f, int offset, int whence);

Parameter


Parameter	Description
f	File whose pointer will be set.
offset	Number of bytes the position of the pointer moves against whence.
whence.	Position defined as a CTRL constant; SEEK_SET start of the files (starts with 0) SEEK_CUR current position SEEK_END ende of file

Return value

In the event of errors, the function returns -1 or EOF otherwise, 0.

Error

If incorrect data types are used or if a file is not open.

Description

The fseek sets the file position indicator for the stream pointed to by f. The new position measured in bytes is obtained by adding offset bytes file to the position of whence. If whence is set to SEEK:SET, SEEK_CUR or SEEK _END, the offset is relative to the start of the file, the current position or the end of a file, respectivly.

Example

The following example opens a file, obtains the position of the pointer and sets the position to different values.

main()
{
  int tell, seek, offset, whence;
  file f;
  string dat, mod;
  f=fopen("C:/TEMP/Abb.txt", "r+"); // Open file
  // tell at the begin to 0
  tell=ftell(f);
  DebugN(tell); // 0
  // set pointer to 30
  seek=fseek(f, 30, SEEK_SET);
  tell=ftell(f);
  DebugN(tell);// 30
  // set pointer to 30 from the current position
  seek=fseek(f, 30, SEEK_CUR);
  tell=ftell(f);
  DebugN(tell); // 60
  // set pointer to the end + 60
  seek=fseek(f, 60, SEEK_END);
  tell=ftell(f);
  DebugN(tell); // 8224
  // set pointer to the end
  seek=fseek(f, 0, SEEK_END);
  tell=ftell(f);
  DebugN(tell); // 8164
  // set pointer again to end + 60
  seek=fseek(f, 60, SEEK_CUR);
  tell=ftell(f);
  DebugN(tell); // 8224
}

Assignment

File functions

Availability

CTRL