safe_to_extend

SFL
Version 2.11

`safe_to_extend`

#include "sflfile.h"
Bool
safe_to_extend (
    const char *filename)

Synopsis

Handles system-specific case of extending a file that may not be in a valid state for such an operation. Returns TRUE if the extend can go ahead; returns FALSE if the extend cannot be permitted. Under MS-DOS and Windows, if the last byte in the file is Ctrl-Z (26) the file is truncated by 1 position to remove this character.

Source Code - (sflfile.c)

{
#if (defined (MSDOS_FILESYSTEM))
    int  handle;                        /*  Opened file handle               */
    char endoffile;                     /*  Last character in file           */

    ASSERT (filename);

    if (system_devicename (filename))
        return (FALSE);                 /*  Not allowed on device names      */

    handle = open (filename, O_RDWR + O_BINARY, S_IREAD | S_IWRITE);
    if (handle)                         /*  If not found, ignore             */
      {
        lseek (handle, -1, SEEK_END);
        read  (handle, &endoffile, 1);
        if (endoffile == 26)
            chsize (handle, filelength (handle) - 1);

        close (handle);
      }
#endif
    return (TRUE);
}

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