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Beginner
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pthread_atfork link error with IPP

I am statically linking to the ipp, umc & uic libraries.I am using IPP 6.1.6.063 and have downloaded the 6.1 sample code. I am using g++.

I can build my own shared object that statically links to ipp and umc, but when I try to build an application that links to my shared object, I get the following link error:

/opt/intel/ipp/6.1.6.063/ia32/sharedlib/libiomp5.so: undefined reference to `pthread_atfork'

I did see the following note in this article:
Error message: /opt/intel/ipp/6.0.0.045/em64t/sharedlib/libiomp5.so: undefined reference to `pthread_atfork'
  • Please make sure to link "-lpthread" library in your command line.

I do have -lpthread specified, but the error still occurs. Here are my ipp library lists:

IPP_LIBS = "${IPP_DIR}/lib/libippdcemerged$(IPP_FILE_EXT).a" \\
"${IPP_DIR}/lib/libippdcmerged$(IPP_FILE_EXT).a""${IPP_DIR}/lib/libippccemerged$(IPP_FILE_EXT).a" \\
"${IPP_DIR}/lib/libippccmerged$(IPP_FILE_EXT).a""${IPP_DIR}/lib/libippcvemerged$(IPP_FILE_EXT).a" \\
"${IPP_DIR}/lib/libippcvmerged$(IPP_FILE_EXT).a""${IPP_DIR}/lib/libippjemerged$(IPP_FILE_EXT).a" \\
"${IPP_DIR}/lib/libippjmerged$(IPP_FILE_EXT).a" "${IPP_DIR}/lib/libippvcemerged$(IPP_FILE_EXT).a" \\
"${IPP_DIR}/lib/libippvcmerged$(IPP_FILE_EXT).a""${IPP_DIR}/lib/libippiemerged$(IPP_FILE_EXT).a" \\
"${IPP_DIR}/lib/libippimerged$(IPP_FILE_EXT).a" "${IPP_DIR}/lib/libippsemerged$(IPP_FILE_EXT).a" \\
"${IPP_DIR}/lib/libippsmerged$(IPP_FILE_EXT).a" "${IPP_DIR}/lib/libippcore$(IPP_FILE_EXT).a" \\
"${IPP_DIR}/sharedlib/libiomp5.so"

UIC_LIBS = "${UIC_IMAGE_DIR}/_bin/linux$(IPP_LIB_ARCH)_/lib/uic_core_l.a" \\
"${UIC_IMAGE_DIR}/_bin/linux$(IPP_LIB_ARCH)_/lib/uic_io_l.a" \\
"${UIC_IMAGE_DIR}/_bin/linux$(IPP_LIB_ARCH)_/lib/uic_jpeg_enc_l.a" \\
"${UIC_IMAGE_DIR}/_bin/linux$(IPP_LIB_ARCH)_/lib/uic_jpeg_dec_l.a" \\
"${UIC_IMAGE_DIR}/_bin/linux$(IPP_LIB_ARCH)_/lib/uic_jpeg_common_l.a"

UMC_LIBS ="${UMC_AVCODEC_DIR}/_bin/linux$(IPP_LIB_ARCH)_/lib/libmpeg4_mux.a" \\
"${UMC_AVCODEC_DIR}/_bin/linux$(IPP_LIB_ARCH)_/lib/libscene_analyzer.a" \\
"${UMC_AVCODEC_DIR}/_bin/linux$(IPP_LIB_ARCH)_/lib/libh264_enc.a" \\
"${UMC_AVCODEC_DIR}/_bin/linux$(IPP_LIB_ARCH)_/lib/libcolor_space_converter.a" \\
"${UMC_AVCODEC_DIR}/_bin/linux$(IPP_LIB_ARCH)_/lib/libumc_io.a" \\
"${UMC_AVCODEC_DIR}/_bin/linux$(IPP_LIB_ARCH)_/lib/libmedia_buffers.a" \\
"${UMC_AVCODEC_DIR}/_bin/linux$(IPP_LIB_ARCH)_/lib/libcommon.a" \\
"${UMC_AVCODEC_DIR}/_bin/linux$(IPP_LIB_ARCH)_/lib/libumc.a" \\
"${UMC_AVCODEC_DIR}/_bin/linux$(IPP_LIB_ARCH)_/lib/libvm_plus.a" \\
"${UMC_AVCODEC_DIR}/_bin/linux$(IPP_LIB_ARCH)_/lib/libvm.a"

I have added -lpthread before any of the ipp, uic or umc library lists.

Can anyone tell me what it is I am doing wrong?
Thanks.
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3 Replies
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Beginner
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Adding -lpthread to the application that links to my shared object fixes this. Is there any way to avoid this? Is there a way to link to pthread in my shared object without requiring users to link to pthread in their own applications?
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Beginner
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This is resolved.

Listing -lpthread after the IPP libraries fixed this issue.
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Employee
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Hi,
Nice to know that it works fine, In Linux, linking order is very important.

Regards,
Naveen Gv
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