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

ferror()

Examines whether a file error has been noted.

Synopsis

int ferror(file f);

Parameters


Parameter	Meaning
f	File

Return value

Value is not equal to 0 if f contains errors.

The return value is not a specific error code, that is, it is not possible to derive the cause of an error.

Error

Description

Returns a value not equal to 0 if an error has been noted for f .

Example

main()
{
  file f; // our file
  int err; // error code
  f=fopen("C:/TEMP/TEST.TXT","r"); // open for reading
  err=ferror(f); // export error
  fclose(f); // close file
  if (err!=0) DebugN("Error no. ",err," occurred");
}

Assignment

File function

Availability

CTRL