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Users can now generate the necessary linker args for their own applications using something like: PKG_CONFIG_PATH=build/lib/pkgconfig pkg-config --libs spdk_nvme Dependencies between libraries are included in the generated .pc files, so the user only needs to pass the top-level subsystems or individual SPDK libraries they are using in their application. Modules will automatically be added to the output if the associated library is specified. For example, specifying "spdk_bdev" will include the libraries not only for spdk_bdev, but also all of the bdev modules. Users still need to supply the -Wl,--no-as-needed or -Wl,--whole-archive flags. They cannot be added to the .pc files without increasing the length of the argument string by a factor of 15x to 20x. Modify the test/external_code/hello_world Makefile to use pkg-config to ensure this gets tested at some level in our autotest environment. Signed-off-by: Jim Harris <james.r.harris@intel.com> Change-Id: Ie48a75f11969d5d775d514cf10bcb82d197eabfd Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/4371 Community-CI: Broadcom CI Tested-by: SPDK CI Jenkins <sys_sgci@intel.com> Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com> Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
56 lines
2.1 KiB
Markdown
56 lines
2.1 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. Here is an example Makefile snippet that
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shows how to use pkg-config to link an application that uses the SPDK nvme shared
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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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