WRITEFILELINES(3A)                             WRITEFILELINES(3A)



  NAME
       WriteFileLines - asynchronously write lines of data to a
       file


  SYNOPSIS
       int WriteFileLines (line, ready, error, arg, name)
       int (*line)();
       int (*ready)();
       char *(*error)();
       int arg;
       char *name;

  DESCRIPTION
       WriteFileLines writes lines of data to a file.  The name of
       the file to write is in name.  The function line is called
       to obtain a line to write to the file.  It will be called
       from WriteFileLines to obtain the first line to write.  The
       function ready is called when the file has been closed, and
       the function error is called upon an error.  Any function
       may be NULL, in which case it will not be called.  When
       there is an error, the file is closed, so exactly one of the
       two functions ready and error is called.  The argument arg
       is passed to both routines.

       The calling sequence for line is as follows:

            char *line (arg, error, buf, length)
            int arg;
            int error;
            char *buf;
            int length;

       The user-supplied argument to WriteFileLines is in arg.  The
       error code, error, is always zero.  The line and its length
       are in buf and length.  The length includes the terminating
       newline, but not the zero byte.  The line function returns a
       buffer for the next line or NULL.  The file will be closed
       if NULL is returned, causing the ready function to be
       called.  The buffer may be the same address passed by the


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  WRITEFILELINES(3A)                             WRITEFILELINES(3A)



       parameter buf, or it may be another malloced area of at
       least BUFSIZ bytes.  The application is responsible for
       freeing the buffer, sometime after the next call to one of
       the line or ready functions.

       The calling sequence for ready is as follows:

            ready (arg)
            int arg;

       The argument arg is the argument supplied to WriteFileLines.

       The calling sequence for error is as follows:

            error (arg, errno)
            int arg;
            int errno;

       The user-supplied data to WriteFileLines is passed in arg
       and an error code interpreted the same as the system global
       variable errno is passed in errno .

       WriteFileLines returns -1 if there was an error setting up
       the I/O procedure, or zero on success.

  NOTES
       There are lower-level asynchronous I/O routines AddIoProc
       and RemoveIoProc that provide greater flexibility at the
       expense of greater coding effort.  WritePipeLines uses these
       routines to set up an asynchronous write procedure.

  SEE ALSO
       XtAppAddInput(3Xt), XtRemoveInput(3Xt), AddIoProc(3A),
       RemoveIoProc(3A), ReadFileData(3A), ReadFileLines(3A),
       ReadFileStrings(3A), ReadPipeData(3A), ReadPipeLines(3A),
       WriteFileData(3A), WritePipeData(3A), WritePipeLines(3A)






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