vcs-svn / line_buffer.txton commit compat: fall back on __va_copy if available (26db0f2)
   1line_buffer API
   2===============
   3
   4The line_buffer library provides a convenient interface for
   5mostly-line-oriented input.
   6
   7Each line is not permitted to exceed 10000 bytes.  The provided
   8functions are not thread-safe or async-signal-safe, and like
   9`fgets()`, they generally do not function correctly if interrupted
  10by a signal without SA_RESTART set.
  11
  12Calling sequence
  13----------------
  14
  15The calling program:
  16
  17 - specifies a file to read with `buffer_init`
  18 - processes input with `buffer_read_line`, `buffer_read_string`,
  19   `buffer_skip_bytes`, and `buffer_copy_bytes`
  20 - closes the file with `buffer_deinit`, perhaps to start over and
  21   read another file.
  22
  23Before exiting, the caller can use `buffer_reset` to deallocate
  24resources for the benefit of profiling tools.
  25
  26Functions
  27---------
  28
  29`buffer_init`::
  30        Open the named file for input.  If filename is NULL,
  31        start reading from stdin.  On failure, returns -1 (with
  32        errno indicating the nature of the failure).
  33
  34`buffer_deinit`::
  35        Stop reading from the current file (closing it unless
  36        it was stdin).  Returns nonzero if `fclose` fails or
  37        the error indicator was set.
  38
  39`buffer_read_line`::
  40        Read a line and strip off the trailing newline.
  41        On failure or end of file, returns NULL.
  42
  43`buffer_read_string`::
  44        Read `len` characters of input or up to the end of the
  45        file, whichever comes first.  Returns NULL on error.
  46        Returns whatever characters were read (possibly "")
  47        for end of file.
  48
  49`buffer_copy_bytes`::
  50        Read `len` bytes of input and dump them to the standard output
  51        stream.  Returns early for error or end of file.
  52
  53`buffer_skip_bytes`::
  54        Discards `len` bytes from the input stream (stopping early
  55        if necessary because of an error or eof).
  56
  57`buffer_reset`::
  58        Deallocates non-static buffers.