Re: Run-time dynamic linking in grep

[Jim Meyering]

Reuben Thomas wrote:
...
> From 0fcaa65199a64239a3552ca4bbbdd7fb1edaca71 Mon Sep 17 00:00:00 2001
> From: Reuben Thomas <address@hidden>
> Date: Fri, 21 Jan 2011 13:21:32 +0000
> Subject: [PATCH] Add --decompress flag for transparent decompression using 
> zlib.
>
> ---
>  configure.ac |   14 ++++++++++++++
>  src/main.c   |   26 +++++++++++++++++++++++++-
>  2 files changed, 39 insertions(+), 1 deletions(-)

Thanks, but you must have left out some important pieces.
That didn't even compile, due to lack of gl_gzdopen declaration on F14.
Once compiled, the --decompress option did nothing, since do_decompress
was never set.

I made these changes:

diff --git a/src/main.c b/src/main.c
index 26fec76..d333040 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1264,7 +1264,7 @@ grepfile (char const *file, struct stats *stats)
 #if defined HAVE_LIBZ
       if (do_decompress)
        {
-         bufgz = dl_gzdopen (fd, "rb");
+         bufgz = gzdopen (desc, "rb");
          if (bufgz == NULL)
            {
              if (errno != 0)
@@ -2060,6 +2060,10 @@ main (int argc, char **argv)
           }
         break;

+      case DECOMPRESS_OPTION:
+        do_decompress = 1;
+        break;
+
       case EXCLUDE_OPTION:
         if (!excluded_patterns)
           excluded_patterns = new_exclude ();

But --decompress still didn't work, because bufgz is set but never used.

With each patch, please ensure at the very least
that "make" (preferably "make distcheck") still passes.
Also, please include a more detailed log entry,
and it'd be nice to add a minimal test that exercises
the new code.
Last but not least, please include
  - a blurb in NEWS
  - description of the new option in doc/grep.texi

----------------------------------------------------------
However, I am left wondering how useful this option would
be when it applies only to gzip'd data.
What about bzip2 and xz?
While gzip is still ubiquitous, it is obviously inferior to xz.