grep doc: add --break / --heading / -W to synopsis

[git.git] / vcs-svn / line_buffer.txt

diff --git a/vcs-svn/line_buffer.txt b/vcs-svn/line_buffer.txt
index 8906fb1f505e125ea58fd7a15c4f13bb0dc78f27..8e139eb22df0f44ba0b805b374943dd5d12e8437 100644 (file)
--- a/vcs-svn/line_buffer.txt
+++ b/vcs-svn/line_buffer.txt
@@ -14,22 +14,46 @@ Calling sequence
 
 The calling program:
 
+ - initializes a `struct line_buffer` to LINE_BUFFER_INIT
  - specifies a file to read with `buffer_init`
- - processes input with `buffer_read_line`, `buffer_read_string`,
-   `buffer_skip_bytes`, and `buffer_copy_bytes`
+ - processes input with `buffer_read_line`, `buffer_skip_bytes`,
+   and `buffer_copy_bytes`
  - closes the file with `buffer_deinit`, perhaps to start over and
    read another file.
 
-Before exiting, the caller can use `buffer_reset` to deallocate
-resources for the benefit of profiling tools.
+When finished, the caller can use `buffer_reset` to deallocate
+resources.
+
+Using temporary files
+---------------------
+
+Temporary files provide a place to store data that should not outlive
+the calling program.  A program
+
+ - initializes a `struct line_buffer` to LINE_BUFFER_INIT
+ - requests a temporary file with `buffer_tmpfile_init`
+ - acquires an output handle by calling `buffer_tmpfile_rewind`
+ - uses standard I/O functions like `fprintf` and `fwrite` to fill
+   the temporary file
+ - declares writing is over with `buffer_tmpfile_prepare_to_read`
+ - can re-read what was written with `buffer_read_line`,
+   `buffer_copy_bytes`, and so on
+ - can reuse the temporary file by calling `buffer_tmpfile_rewind`
+   again
+ - removes the temporary file with `buffer_deinit`, perhaps to
+   reuse the line_buffer for some other file.
+
+When finished, the calling program can use `buffer_reset` to deallocate
+resources.
 
 Functions
 ---------
 
-`buffer_init`::
-       Open the named file for input.  If filename is NULL,
-       start reading from stdin.  On failure, returns -1 (with
-       errno indicating the nature of the failure).
+`buffer_init`, `buffer_fdinit`::
+       Open the named file or file descriptor for input.
+       buffer_init(buf, NULL) prepares to read from stdin.
+       On failure, returns -1 (with errno indicating the nature
+       of the failure).
 
 `buffer_deinit`::
        Stop reading from the current file (closing it unless
@@ -40,19 +64,14 @@ Functions
        Read a line and strip off the trailing newline.
        On failure or end of file, returns NULL.
 
-`buffer_read_string`::
-       Read `len` characters of input or up to the end of the
-       file, whichever comes first.  Returns NULL on error.
-       Returns whatever characters were read (possibly "")
-       for end of file.
-
 `buffer_copy_bytes`::
        Read `len` bytes of input and dump them to the standard output
        stream.  Returns early for error or end of file.
 
 `buffer_skip_bytes`::
        Discards `len` bytes from the input stream (stopping early
-       if necessary because of an error or eof).
+       if necessary because of an error or eof).  Return value is
+       the number of bytes successfully read.
 
 `buffer_reset`::
        Deallocates non-static buffers.