From 9f9cfdc5917e63a571b123d90637785b2aa4c60b Mon Sep 17 00:00:00 2001
From: Piotr Pelplinski <piotr.pelplinski@intel.com>
Date: Wed, 24 Oct 2018 09:16:07 +0200
Subject: [PATCH] doc: update doc with instructions for building shared lib

Signed-off-by: Piotr Pelplinski <piotr.pelplinski@intel.com>
Change-Id: Idc3aae5a0486008a8a593c13135f8f785dc73100

Reviewed-on: https://review.gerrithub.io/430538
Reviewed-by: Lance Hartmann <lance.hartmann@oracle.com>
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
---
 README.md | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/README.md b/README.md
index e48a8450b..5faa2d58d 100644
--- a/README.md
+++ b/README.md
@@ -26,6 +26,7 @@ The development kit currently includes:
 * [Unit Tests](#tests)
 * [Vagrant](#vagrant)
 * [Advanced Build Options](#advanced)
+* [Shared libraries](#shared)
 * [Hugepages and Device Binding](#huge)
 * [Example Code](#examples)
 * [Contributing](#contributing)
@@ -156,6 +157,33 @@ values in `mk/config.mk`. This can be useful if you, for example, generate
 a `mk/config.mk` using the `configure` script and then have one or two
 options (i.e. debug builds) that you wish to turn on and off frequently.
 
+<a id="shared"></a>
+## Shared libraries
+
+By default, the build of the SPDK yields static libraries against which
+the SPDK applications and examples are linked.
+Configure option `--with-shared` provides the ability to produce SPDK shared
+libraries, in addition to the default static ones.  Use of this flag also
+results in the SPDK executables linked to the shared versions of libraries.
+SPDK shared libraries by default, are located in `./build/lib`.  This includes
+the single SPDK shared lib encompassing all of the SPDK static libs
+(`libspdk.so`) as well as individual SPDK shared libs corresponding to each
+of the SPDK static ones.
+
+In order to start a SPDK app linked with SPDK shared libraries, make sure
+to do the following steps:
+- run ldconfig specifying the directory containing SPDK shared libraries
+- provide proper `LD_LIBRARY_PATH`
+
+Linux:
+
+~~~{.sh}
+./configure --with-shared
+make
+ldconfig -v -n ./build/lib
+LD_LIBRARY_PATH=./build/lib/ ./app/spdk_tgt/spdk_tgt
+~~~
+
 <a id="huge"></a>
 ## Hugepages and Device Binding