1b837766f0
The documentation around static linking in doc/libraries.md is improved. This is achieved using examples and explaning the requirements that arise from the use of constructor functions. Additionally, the documentation around the same subject is improved in doc/pkgconfig.md Signed-off-by: Dantali0n <info@dantalion.nl> Change-Id: I3b11db441d14d2e8d792a22de2bd17fe5c2389fd Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/6798 Community-CI: Mellanox Build Bot Reviewed-by: Ben Walker <benjamin.walker@intel.com> Reviewed-by: Aleksey Marchuk <alexeymar@mellanox.com> Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
57 lines
2.2 KiB
Markdown
57 lines
2.2 KiB
Markdown
# Linking SPDK applications with pkg-config {#pkgconfig}
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The SPDK build system generates pkg-config files to facilitate linking
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applications with the correct set of SPDK and DPDK libraries. Using pkg-config
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in your build system will ensure you do not need to make modifications
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when SPDK adds or modifies library dependencies.
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If your application is using the SPDK nvme library, you would use the following
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to get the list of required SPDK libraries:
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~~~
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PKG_CONFIG_PATH=/path/to/spdk/build/lib/pkgconfig pkg-config --libs spdk_nvme
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~~~
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To get the list of required SPDK and DPDK libraries to use the DPDK-based
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environment layer:
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~~~
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PKG_CONFIG_PATH=/path/to/spdk/build/lib/pkgconfig pkg-config --libs spdk_env_dpdk
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~~~
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When linking with static libraries, the dependent system libraries must also be
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specified. To get the list of required system libraries:
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~~~
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PKG_CONFIG_PATH=/path/to/spdk/build/lib/pkgconfig pkg-config --libs spdk_syslibs
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~~~
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Note that SPDK libraries use constructor functions liberally, so you must surround
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the library list with extra linker options to ensure these functions are not dropped
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from the resulting application binary. With shared libraries this is achieved through
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the `-Wl,--no-as-needed` parameters while with static libraries `-Wl,--whole-archive`
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is used. Here is an example Makefile snippet that shows how to use pkg-config to link
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an application that uses the SPDK nvme shared library:
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~~~
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PKG_CONFIG_PATH = $(SPDK_DIR)/build/lib/pkgconfig
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SPDK_LIB := $(shell PKG_CONFIG_PATH="$(PKG_CONFIG_PATH)" pkg-config --libs spdk_nvme
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DPDK_LIB := $(shell PKG_CONFIG_PATH="$(PKG_CONFIG_PATH)" pkg-config --libs spdk_env_dpdk
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app:
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$(CC) -o app app.o -pthread -Wl,--no-as-needed $(SPDK_LIB) $(DPDK_LIB) -Wl,--as-needed
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~~~
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If using the SPDK nvme static library:
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~~~
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PKG_CONFIG_PATH = $(SPDK_DIR)/build/lib/pkgconfig
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SPDK_LIB := $(shell PKG_CONFIG_PATH="$(PKG_CONFIG_PATH)" pkg-config --libs spdk_nvme
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DPDK_LIB := $(shell PKG_CONFIG_PATH="$(PKG_CONFIG_PATH)" pkg-config --libs spdk_env_dpdk
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SYS_LIB := $(shell PKG_CONFIG_PATH="$(PKG_CONFIG_PATH)" pkg-config --libs --static spdk_syslibs
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app:
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$(CC) -o app app.o -pthread -Wl,--whole-archive $(SPDK_LIB) $(DPDK_LIB) -Wl,--no-whole-archive \
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$(SYS_LIB)
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~~~
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