C Language and Libraries Help (clang.hlp) (Table of Contents; Topic list)
Important Notice
The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.
fopen
 Summary Example                         Up Contents Index Back
─────Run-Time Library───────────────────────────────────────────────────────
 
     The fopen function opens the file specified by <filename>. The
     character string <mode> specifies the type of access requested
     for the file. Because fopen assumes that the <mode> argument is
     a string literal, you must use quotation marks. For example:
 
          fopen( infile, "rtc" );
 
     The valid types are "r" (read), "w" (write), and "a" (append).
     Any of these can be followed by a "+", which allows both read and
     write operations. The translation mode for new lines can be
     specified by adding "t" (text) or "b" (binary) to the <mode>
     string.
 
     In addition, you can use either "c" (commit) or "n" (no-commit)
     in the <mode> string. These two characters control whether the
     opened file is written directly to disk ("c") or to the operating
     system ("n") on an explicit call to either the fflush or the
     _flushall function.
 
     The fopen function defaults to "n". Explicit use of either "c" or
     "n" overrides the global commit flag. The global commit flag
     defaults to "n" unless you explicitly link your program with
     COMMODE.OBJ.
 
     The "t", "c", and "n" options are not part of the ANSI standard,
     but are instead Microsoft extensions and should not be used where
     ANSI portability is desired.
 
     See: BINMODE.OBJ
          COMMODE.OBJ
 
     See also the individual constants for access type and translation
     mode:
          Access Types
          Commit-to-Disk Modes
          Translation Modes
 
 
     Return Value
 
     The fopen function returns a pointer to the open file. A null
     pointer value indicates an error.
                                    -♦-