BCX File Management Functions

APPEXENAME$ function
APPEXEPATH$ function
BCXPATH$ function
BFF$ function
CLOSE statement
COMBOBOXLOADFILE statement
COPYFILE statement
EOF statement
EXIST function
FILELOCKED function
FINDFIRST$ function
FINDNEXT$ function
FREEFILE function
GETFILENAME$ function
GETATTR statement
KILL statement
LISTBOXLOADFILE statement
LOADFILE$ function
LOC function
LOF function
LOOKAHEAD$ function
OPEN statement
PELLESPATH$ function
REC function
RECCOUNT function
RECORD function
RECLEN statement
RENAME statement
REWIND statement
SETATTR statement

FILELOCKED function

Purpose:

FILELOCKED determines whether or not a file can be opened.

RetVal = FILELOCKED(FileName AS STRING)

$FILETEST ON ... $FILETEST OFF directive

Purpose:

The $FILETEST ON or $FILETEST OFF directives specify whether or not to suppress the automatic failure checking when using OPEN and CLOSE statements.

👉 In the C translation of OPEN and CLOSE statements, BCX automatically adds code to check for the existence of the file that is being opened or closed. If the file being opened does not exist, the program will exit and a "Can't open file FileName$" statement will be sent to stdout.

$FILETEST ON or $FILETEST OFF

OPEN statement

Purpose:

The OPEN statement opens a file, specifies a streaming mode, and associates a file handle name with the file.

Every OPEN statement must be terminated, eventually, with a CLOSE statement. See the CLOSE section below for details.

OPEN FileName FOR StreamingMode AS hFile

Remarks:

👉 In the C translation of OPEN and CLOSE statements, BCX automatically adds code to check for the existence of the file that is being opened or closed. If the file being opened does not exist, the program will exit and a "Can't open file FileName$" statement will be sent to stdout.

CLOSE statement

Purpose:

The CLOSE statement causes the file stream associated with a file handle to be flushed and the file to be closed.

CLOSE hFile

CLOSE

Remarks:

👉 The CLOSE statement allows multiple file handles on one line. For example,

CLOSE #1, #2, FP3, MyDocHandle

Opening Text Files

OPEN FileName FOR INPUT statement

Purpose:

Streaming Mode: open text file for reading.

OPEN FileName FOR INPUT AS hFile

OPEN FileName FOR OUTPUT statement

Purpose:

Streaming Mode: truncate contents of existing file to zero length or create text file for writing.

OPEN FileName FOR OUTPUT AS hFile

OPEN FileName FOR APPEND statement

Purpose:

Streaming Mode: truncate contents of existing file to zero length or create text file for writing.

OPEN FileName FOR APPEND AS hFile

Opening Binary Files

OPEN FileName FOR BINARY statement

Purpose:

Streaming Mode: open binary file for update (reading and writing).

OPEN FileName FOR BINARY AS hFile

OPEN FileName FOR BINARY NEW statement

Purpose:

Streaming Mode: truncate contents of existing file to zero length or create binary file for update.

OPEN FileName FOR BINARY NEW AS hFile

OPEN FileName FOR BINARY APPEND statement

Purpose:

Streaming Mode: append; open or create binary file for update, writing at end-of-file.

OPEN FileName FOR BINARY APPEND AS hFile

OPEN FileName FOR BINARY INPUT statement

Purpose:

Streaming Mode: open binary file for reading.

OPEN FileName FOR BINARY INPUT AS hFile

OPEN FileName FOR BINARY OUTPUT statement

Purpose:

Streaming Mode: open binary file for update (reading and writing).

OPEN FileName FOR BINARY OUTPUT AS hFile

Remarks:

Expressions such as:

OPEN EXTRACT$(FileName,".") & ".bas" FOR INPUT AS FP1

are valid.

File Handle Names

• QBASIC syle file handle names using the #number syntax, for example, #1, #2, #3, are supported in BCX. If the #number syntax is used, BCX converts, for example, #1, #2, #3 to FP1, FP2, FP3 in the C code translation.
• A file handle name can be explicitly created as shown in this example.

  DIM MyFileHandle@ ' BCX Reserves @ for C FILE* data types
  OPEN "new.txt" FOR OUTPUT AS FP1
  MyFileHandle@ = FP1
  FPRINT MyFileHandle@, "This is a test"
  CLOSE FP1
  

  or, for example, like this

  GLOBAL DYNAMIC FHandles[12] AS FILE PTR
  
  LOCAL DYNAMIC FHandles[12] AS FILE PTR
  

• When passing a file handle name to a SUB or FUNCTION use AS FILE as the data type specifier for the file handle name argument in the parameter list of the procedure as is done with "ABC" in the snippet below.

  OPEN "new.txt" FOR INPUT AS FP1
  PARSE$(FP1)
  CLOSE FP1
  
  FUNCTION PARSE$ (ABC AS FILE)
    LOCAL Buffer$
    LINE INPUT ABC, Buffer$
    PRINT Buffer$
    FUNCTION = Buffer$
  END FUNCTION
  

• In the snippet below, the file handle name MyFP1 will be LOCAL in scope to the subroutine FileTest.

  SUB FileTest ()
   DIM RAW MyFP1 AS FILE
   OPEN "test.txt" FOR BINARY AS MyFP1
   CLOSE MyFP1
  END SUB
  

• The C runtime file system and the Windows file system are largely distinct from each other which can complicate certain operations when trying to interface between the two of them. The code below shows one example that allows a C runtime file system FILE POINTER to be used with a Windows function that expects a Windows FILE HANDLE.
  
  The code below allows a filename to be retrieved from an open file number. This can be a useful function for trapping errors in programs with lots of complicated file I/O.

  OPEN "Junk.txt" FOR OUTPUT AS FP1
  PRINT FilenameFromFileNumber$(FP1) ' Should display Your_Drive:\Your_Path\Junk.txt 
  CLOSE FP1
  KILL "Junk.txt"
  
  FUNCTION FilenameFromFileNumber$ (FP AS FILE) ' This might cause problems on networked files. 
   DIM Tmp$ * 2048
   IF GetFinalPathNameByHandle((HANDLE)_get_osfhandle(_fileno(FP)), Tmp$, 2048, 0) THEN strcpy(Tmp, Tmp+4)
   FUNCTION = Tmp$
  END FUNCTION
  

BCX Console Sample Programs using the OPEN function.

• S10.bas
• S103.bas
• S113.bas
• S115.bas