g++ - linking stage (-L flag) not working
1
I am new to C++ and am trying to figure out where in the compiling process my error is. Apologies, if this question is unclear, I'm not sure what information to provide.
Reference information: The directory "mbedtls/lib/" contains two .a (archive) files, "libmbedtls_SGX_t.a" and "libmbedtls_SGX_u.a".
I am using a Makefile, which runs the following commands in order. The commands seem to run error free:
cc -m64 -O2 -fPIC -Wno-attributes -IApp -I/opt/intel/sgxsdk/include -Imbedtls/include -DNDEBUG -UEDEBUG -UDEBUG -c App/Enclave_u.c -o App/Enclave_u.o
g++ -m64 -O2 -fPIC -Wno-attributes -IApp -I/opt/intel/sgxsdk/include -Imbedtls/include -DNDEBUG -UEDEBUG -UDEBUG -std=c++11 -c App/App.cpp -o App/App.o
g++ -m64 -O2 -fPIC -Wno-attributes -IApp -I/opt/intel/sgxsdk/include -Imbedtls/include -DNDEBUG -UEDEBUG -UDEBUG -std=c++11 -c App/sgx_utils/sgx_utils.cpp -o App/sgx_utils/sgx_utils.o
After running those commands, it runs this command:
g++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2 -L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread -Lmbedtls/lib/ -lsgx_uae_service_sim
However, this command produces an error:
App/Enclave_u.o: In function `Enclave_ocall_print_string':
Enclave_u.c:(.text+0x9): undefined reference to `ocall_print_string'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_free':
Enclave_u.c:(.text+0x28): undefined reference to `ocall_mbedtls_net_free'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_recv_timeout':
Enclave_u.c:(.text+0x54): undefined reference to `ocall_mbedtls_net_recv_timeout'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_send':
Enclave_u.c:(.text+0x71): undefined reference to `ocall_mbedtls_net_send'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_recv':
Enclave_u.c:(.text+0x91): undefined reference to `ocall_mbedtls_net_recv'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_usleep':
Enclave_u.c:(.text+0xa8): undefined reference to `ocall_mbedtls_net_usleep'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_set_nonblock':
Enclave_u.c:(.text+0xc9): undefined reference to `ocall_mbedtls_net_set_nonblock'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_set_block':
Enclave_u.c:(.text+0xe9): undefined reference to `ocall_mbedtls_net_set_block'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_accept':
Enclave_u.c:(.text+0x119): undefined reference to `ocall_mbedtls_net_accept'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_bind':
Enclave_u.c:(.text+0x144): undefined reference to `ocall_mbedtls_net_bind'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_connect':
Enclave_u.c:(.text+0x164): undefined reference to `ocall_mbedtls_net_connect'
collect2: error: ld returned 1 exit status
Makefile:184: recipe for target 'app' failed
I don't know why this error is being produced. My last command includes the flag -Lmbedtls/lib/ which should resolve these undefined references by linking the archive files (specifically - libmbedtls_SGX_u.a) to the executable. However, clearly this is not happening.
Do I need to link the archive files earlier in the compile process? I.e - instead of using the flag -Lmbedtls/lib/ in the final g++ command, should I be using it in both of the previous g++ commands?
Update: Adding the flag -Lmbedtls/lib/ to the previous 2 g++ commands (the ones that generated App.o and sgx_utils.o) did not change anything. The error remains.
c++ g++ static-libraries static-linking sgx
asked Nov 12 '18 at 22:11
Roymunson
1,65221638
add a comment |
1
I am new to C++ and am trying to figure out where in the compiling process my error is. Apologies, if this question is unclear, I'm not sure what information to provide.
Reference information: The directory "mbedtls/lib/" contains two .a (archive) files, "libmbedtls_SGX_t.a" and "libmbedtls_SGX_u.a".
I am using a Makefile, which runs the following commands in order. The commands seem to run error free:
cc -m64 -O2 -fPIC -Wno-attributes -IApp -I/opt/intel/sgxsdk/include -Imbedtls/include -DNDEBUG -UEDEBUG -UDEBUG -c App/Enclave_u.c -o App/Enclave_u.o
g++ -m64 -O2 -fPIC -Wno-attributes -IApp -I/opt/intel/sgxsdk/include -Imbedtls/include -DNDEBUG -UEDEBUG -UDEBUG -std=c++11 -c App/App.cpp -o App/App.o
g++ -m64 -O2 -fPIC -Wno-attributes -IApp -I/opt/intel/sgxsdk/include -Imbedtls/include -DNDEBUG -UEDEBUG -UDEBUG -std=c++11 -c App/sgx_utils/sgx_utils.cpp -o App/sgx_utils/sgx_utils.o
After running those commands, it runs this command:
g++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2 -L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread -Lmbedtls/lib/ -lsgx_uae_service_sim
However, this command produces an error:
App/Enclave_u.o: In function `Enclave_ocall_print_string':
Enclave_u.c:(.text+0x9): undefined reference to `ocall_print_string'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_free':
Enclave_u.c:(.text+0x28): undefined reference to `ocall_mbedtls_net_free'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_recv_timeout':
Enclave_u.c:(.text+0x54): undefined reference to `ocall_mbedtls_net_recv_timeout'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_send':
Enclave_u.c:(.text+0x71): undefined reference to `ocall_mbedtls_net_send'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_recv':
Enclave_u.c:(.text+0x91): undefined reference to `ocall_mbedtls_net_recv'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_usleep':
Enclave_u.c:(.text+0xa8): undefined reference to `ocall_mbedtls_net_usleep'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_set_nonblock':
Enclave_u.c:(.text+0xc9): undefined reference to `ocall_mbedtls_net_set_nonblock'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_set_block':
Enclave_u.c:(.text+0xe9): undefined reference to `ocall_mbedtls_net_set_block'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_accept':
Enclave_u.c:(.text+0x119): undefined reference to `ocall_mbedtls_net_accept'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_bind':
Enclave_u.c:(.text+0x144): undefined reference to `ocall_mbedtls_net_bind'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_connect':
Enclave_u.c:(.text+0x164): undefined reference to `ocall_mbedtls_net_connect'
collect2: error: ld returned 1 exit status
Makefile:184: recipe for target 'app' failed
I don't know why this error is being produced. My last command includes the flag -Lmbedtls/lib/ which should resolve these undefined references by linking the archive files (specifically - libmbedtls_SGX_u.a) to the executable. However, clearly this is not happening.
Do I need to link the archive files earlier in the compile process? I.e - instead of using the flag -Lmbedtls/lib/ in the final g++ command, should I be using it in both of the previous g++ commands?
Update: Adding the flag -Lmbedtls/lib/ to the previous 2 g++ commands (the ones that generated App.o and sgx_utils.o) did not change anything. The error remains.
c++ g++ static-libraries static-linking sgx
asked Nov 12 '18 at 22:11
Roymunson
1,65221638
3
-Ltells g++ where to look for.afiles, not to actually link them, you have to specify-llibmbedtls_SGX_u
– orhtej2
Nov 12 '18 at 22:14
1
In general you should mention files referencing a symbol before the file providing the symbol. Many (not all, but most) linkers will discard any symbol that they have not seen a previous reference to.
– Jesper Juhl
Nov 12 '18 at 22:14
@JesperJuhl Can you explain what the implications of your statement are in terms of the commands I should be executing?
– Roymunson
Nov 12 '18 at 22:16
The implication is that whenever you tell your toolchain to link something you have to name the object files/libraries in an order where the ones that come first are the ones that consume/use symbols and the ones that provide the implementation come after.
– Jesper Juhl
Nov 12 '18 at 22:20
I think -pthread (not -lpthread).
– 2785528
Nov 12 '18 at 23:03
add a comment |
1
1
1
I am new to C++ and am trying to figure out where in the compiling process my error is. Apologies, if this question is unclear, I'm not sure what information to provide.
Reference information: The directory "mbedtls/lib/" contains two .a (archive) files, "libmbedtls_SGX_t.a" and "libmbedtls_SGX_u.a".
I am using a Makefile, which runs the following commands in order. The commands seem to run error free:
cc -m64 -O2 -fPIC -Wno-attributes -IApp -I/opt/intel/sgxsdk/include -Imbedtls/include -DNDEBUG -UEDEBUG -UDEBUG -c App/Enclave_u.c -o App/Enclave_u.o
g++ -m64 -O2 -fPIC -Wno-attributes -IApp -I/opt/intel/sgxsdk/include -Imbedtls/include -DNDEBUG -UEDEBUG -UDEBUG -std=c++11 -c App/App.cpp -o App/App.o
g++ -m64 -O2 -fPIC -Wno-attributes -IApp -I/opt/intel/sgxsdk/include -Imbedtls/include -DNDEBUG -UEDEBUG -UDEBUG -std=c++11 -c App/sgx_utils/sgx_utils.cpp -o App/sgx_utils/sgx_utils.o
After running those commands, it runs this command:
g++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2 -L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread -Lmbedtls/lib/ -lsgx_uae_service_sim
However, this command produces an error:
App/Enclave_u.o: In function `Enclave_ocall_print_string':
Enclave_u.c:(.text+0x9): undefined reference to `ocall_print_string'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_free':
Enclave_u.c:(.text+0x28): undefined reference to `ocall_mbedtls_net_free'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_recv_timeout':
Enclave_u.c:(.text+0x54): undefined reference to `ocall_mbedtls_net_recv_timeout'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_send':
Enclave_u.c:(.text+0x71): undefined reference to `ocall_mbedtls_net_send'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_recv':
Enclave_u.c:(.text+0x91): undefined reference to `ocall_mbedtls_net_recv'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_usleep':
Enclave_u.c:(.text+0xa8): undefined reference to `ocall_mbedtls_net_usleep'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_set_nonblock':
Enclave_u.c:(.text+0xc9): undefined reference to `ocall_mbedtls_net_set_nonblock'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_set_block':
Enclave_u.c:(.text+0xe9): undefined reference to `ocall_mbedtls_net_set_block'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_accept':
Enclave_u.c:(.text+0x119): undefined reference to `ocall_mbedtls_net_accept'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_bind':
Enclave_u.c:(.text+0x144): undefined reference to `ocall_mbedtls_net_bind'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_connect':
Enclave_u.c:(.text+0x164): undefined reference to `ocall_mbedtls_net_connect'
collect2: error: ld returned 1 exit status
Makefile:184: recipe for target 'app' failed
I don't know why this error is being produced. My last command includes the flag -Lmbedtls/lib/ which should resolve these undefined references by linking the archive files (specifically - libmbedtls_SGX_u.a) to the executable. However, clearly this is not happening.
Do I need to link the archive files earlier in the compile process? I.e - instead of using the flag -Lmbedtls/lib/ in the final g++ command, should I be using it in both of the previous g++ commands?
Update: Adding the flag -Lmbedtls/lib/ to the previous 2 g++ commands (the ones that generated App.o and sgx_utils.o) did not change anything. The error remains.
c++ g++ static-libraries static-linking sgx
asked Nov 12 '18 at 22:11
Roymunson
1,65221638
I am new to C++ and am trying to figure out where in the compiling process my error is. Apologies, if this question is unclear, I'm not sure what information to provide.
Reference information: The directory "mbedtls/lib/" contains two .a (archive) files, "libmbedtls_SGX_t.a" and "libmbedtls_SGX_u.a".
I am using a Makefile, which runs the following commands in order. The commands seem to run error free:
cc -m64 -O2 -fPIC -Wno-attributes -IApp -I/opt/intel/sgxsdk/include -Imbedtls/include -DNDEBUG -UEDEBUG -UDEBUG -c App/Enclave_u.c -o App/Enclave_u.o
g++ -m64 -O2 -fPIC -Wno-attributes -IApp -I/opt/intel/sgxsdk/include -Imbedtls/include -DNDEBUG -UEDEBUG -UDEBUG -std=c++11 -c App/App.cpp -o App/App.o
g++ -m64 -O2 -fPIC -Wno-attributes -IApp -I/opt/intel/sgxsdk/include -Imbedtls/include -DNDEBUG -UEDEBUG -UDEBUG -std=c++11 -c App/sgx_utils/sgx_utils.cpp -o App/sgx_utils/sgx_utils.o
After running those commands, it runs this command:
g++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2 -L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread -Lmbedtls/lib/ -lsgx_uae_service_sim
However, this command produces an error:
App/Enclave_u.o: In function `Enclave_ocall_print_string':
Enclave_u.c:(.text+0x9): undefined reference to `ocall_print_string'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_free':
Enclave_u.c:(.text+0x28): undefined reference to `ocall_mbedtls_net_free'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_recv_timeout':
Enclave_u.c:(.text+0x54): undefined reference to `ocall_mbedtls_net_recv_timeout'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_send':
Enclave_u.c:(.text+0x71): undefined reference to `ocall_mbedtls_net_send'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_recv':
Enclave_u.c:(.text+0x91): undefined reference to `ocall_mbedtls_net_recv'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_usleep':
Enclave_u.c:(.text+0xa8): undefined reference to `ocall_mbedtls_net_usleep'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_set_nonblock':
Enclave_u.c:(.text+0xc9): undefined reference to `ocall_mbedtls_net_set_nonblock'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_set_block':
Enclave_u.c:(.text+0xe9): undefined reference to `ocall_mbedtls_net_set_block'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_accept':
Enclave_u.c:(.text+0x119): undefined reference to `ocall_mbedtls_net_accept'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_bind':
Enclave_u.c:(.text+0x144): undefined reference to `ocall_mbedtls_net_bind'
App/Enclave_u.o: In function `Enclave_ocall_mbedtls_net_connect':
Enclave_u.c:(.text+0x164): undefined reference to `ocall_mbedtls_net_connect'
collect2: error: ld returned 1 exit status
Makefile:184: recipe for target 'app' failed
I don't know why this error is being produced. My last command includes the flag -Lmbedtls/lib/ which should resolve these undefined references by linking the archive files (specifically - libmbedtls_SGX_u.a) to the executable. However, clearly this is not happening.
Do I need to link the archive files earlier in the compile process? I.e - instead of using the flag -Lmbedtls/lib/ in the final g++ command, should I be using it in both of the previous g++ commands?
Update: Adding the flag -Lmbedtls/lib/ to the previous 2 g++ commands (the ones that generated App.o and sgx_utils.o) did not change anything. The error remains.
c++ g++ static-libraries static-linking sgx
c++ g++ static-libraries static-linking sgx
asked Nov 12 '18 at 22:11
Roymunson
1,65221638
asked Nov 12 '18 at 22:11
Roymunson
1,65221638
edited Nov 12 '18 at 22:37
asked Nov 12 '18 at 22:11
Roymunson
1,65221638
asked Nov 12 '18 at 22:11
Roymunson
1,65221638
asked Nov 12 '18 at 22:11
Roymunson
1,65221638
1,65221638
3
-Ltells g++ where to look for.afiles, not to actually link them, you have to specify-llibmbedtls_SGX_u
– orhtej2
Nov 12 '18 at 22:14
1
In general you should mention files referencing a symbol before the file providing the symbol. Many (not all, but most) linkers will discard any symbol that they have not seen a previous reference to.
– Jesper Juhl
Nov 12 '18 at 22:14
@JesperJuhl Can you explain what the implications of your statement are in terms of the commands I should be executing?
– Roymunson
Nov 12 '18 at 22:16
The implication is that whenever you tell your toolchain to link something you have to name the object files/libraries in an order where the ones that come first are the ones that consume/use symbols and the ones that provide the implementation come after.
– Jesper Juhl
Nov 12 '18 at 22:20
I think -pthread (not -lpthread).
– 2785528
Nov 12 '18 at 23:03
add a comment |
3
-Ltells g++ where to look for.afiles, not to actually link them, you have to specify-llibmbedtls_SGX_u
– orhtej2
Nov 12 '18 at 22:14
1
In general you should mention files referencing a symbol before the file providing the symbol. Many (not all, but most) linkers will discard any symbol that they have not seen a previous reference to.
– Jesper Juhl
Nov 12 '18 at 22:14
@JesperJuhl Can you explain what the implications of your statement are in terms of the commands I should be executing?
– Roymunson
Nov 12 '18 at 22:16
The implication is that whenever you tell your toolchain to link something you have to name the object files/libraries in an order where the ones that come first are the ones that consume/use symbols and the ones that provide the implementation come after.
– Jesper Juhl
Nov 12 '18 at 22:20
I think -pthread (not -lpthread).
– 2785528
Nov 12 '18 at 23:03
3
3
-L tells g++ where to look for .a files, not to actually link them, you have to specify -llibmbedtls_SGX_u– orhtej2
Nov 12 '18 at 22:14
-L tells g++ where to look for .a files, not to actually link them, you have to specify -llibmbedtls_SGX_u– orhtej2
Nov 12 '18 at 22:14
1
1
In general you should mention files referencing a symbol before the file providing the symbol. Many (not all, but most) linkers will discard any symbol that they have not seen a previous reference to.
– Jesper Juhl
Nov 12 '18 at 22:14
In general you should mention files referencing a symbol before the file providing the symbol. Many (not all, but most) linkers will discard any symbol that they have not seen a previous reference to.
– Jesper Juhl
Nov 12 '18 at 22:14
@JesperJuhl Can you explain what the implications of your statement are in terms of the commands I should be executing?
– Roymunson
Nov 12 '18 at 22:16
@JesperJuhl Can you explain what the implications of your statement are in terms of the commands I should be executing?
– Roymunson
Nov 12 '18 at 22:16
The implication is that whenever you tell your toolchain to link something you have to name the object files/libraries in an order where the ones that come first are the ones that consume/use symbols and the ones that provide the implementation come after.
– Jesper Juhl
Nov 12 '18 at 22:20
The implication is that whenever you tell your toolchain to link something you have to name the object files/libraries in an order where the ones that come first are the ones that consume/use symbols and the ones that provide the implementation come after.
– Jesper Juhl
Nov 12 '18 at 22:20
I think -pthread (not -lpthread).
– 2785528
Nov 12 '18 at 23:03
I think -pthread (not -lpthread).
– 2785528
Nov 12 '18 at 23:03
add a comment |
1 Answer
1
active
oldest
votes
2
As has been mentioned in the comment, only specifying a directory with -L without specifying the name of a library in that directory is useless.
So you have to additionally specify the library names with -l.
So instead of:
g++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2
-L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread
-Lmbedtls/lib/
-lsgx_uae_service_sim
Use:
g++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2
-L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread
-Lmbedtls/lib/ -lmbedtls_SGX_t -lmbedtls_SGX_u
-lsgx_uae_service_sim
answered Nov 12 '18 at 22:21
Codo
50.5k11110148
I ran the commandg++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2 -L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread -Lmbedtls/lib/ -llibmbedtls_SGX_u -lsgx_uae_service_simbecause I only wanted to linklibmbedtls_SGX_u.a. However, suprisingly, I am getting the error: "cannot find -llibmbedtls_SGX_u" even though I am very sure that "libmbedtls_SGX_u.a" is inside of the "mbedtls/lib" directory.
– Roymunson
Nov 12 '18 at 22:28
2
The command-lis peculiar. You have to specify the library name without the leadinglib. So it's just-lmbedtls_SGX_uinstead of-llibmbedtls_SGX_u. My initial answer was partially incorrect in that respect and you have probably been very quick in copying it.
– Codo
Nov 12 '18 at 22:32
Oh whoops, I thought you made a mistake by omitting the lib, so I left it in.
– Roymunson
Nov 12 '18 at 22:34
Where can I go to learn more about how to use the g++ compiler, so I can avoid making these mistakes in the future?
– Roymunson
Nov 12 '18 at 22:49
I think -pthread (not -lpthread).
– 2785528
Nov 12 '18 at 23:03
|
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2
As has been mentioned in the comment, only specifying a directory with -L without specifying the name of a library in that directory is useless.
So you have to additionally specify the library names with -l.
So instead of:
g++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2
-L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread
-Lmbedtls/lib/
-lsgx_uae_service_sim
Use:
g++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2
-L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread
-Lmbedtls/lib/ -lmbedtls_SGX_t -lmbedtls_SGX_u
-lsgx_uae_service_sim
answered Nov 12 '18 at 22:21
Codo
50.5k11110148
I ran the commandg++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2 -L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread -Lmbedtls/lib/ -llibmbedtls_SGX_u -lsgx_uae_service_simbecause I only wanted to linklibmbedtls_SGX_u.a. However, suprisingly, I am getting the error: "cannot find -llibmbedtls_SGX_u" even though I am very sure that "libmbedtls_SGX_u.a" is inside of the "mbedtls/lib" directory.
– Roymunson
Nov 12 '18 at 22:28
2
The command-lis peculiar. You have to specify the library name without the leadinglib. So it's just-lmbedtls_SGX_uinstead of-llibmbedtls_SGX_u. My initial answer was partially incorrect in that respect and you have probably been very quick in copying it.
– Codo
Nov 12 '18 at 22:32
Oh whoops, I thought you made a mistake by omitting the lib, so I left it in.
– Roymunson
Nov 12 '18 at 22:34
Where can I go to learn more about how to use the g++ compiler, so I can avoid making these mistakes in the future?
– Roymunson
Nov 12 '18 at 22:49
I think -pthread (not -lpthread).
– 2785528
Nov 12 '18 at 23:03
|
show 4 more comments
2
As has been mentioned in the comment, only specifying a directory with -L without specifying the name of a library in that directory is useless.
So you have to additionally specify the library names with -l.
So instead of:
g++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2
-L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread
-Lmbedtls/lib/
-lsgx_uae_service_sim
Use:
g++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2
-L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread
-Lmbedtls/lib/ -lmbedtls_SGX_t -lmbedtls_SGX_u
-lsgx_uae_service_sim
answered Nov 12 '18 at 22:21
Codo
50.5k11110148
I ran the commandg++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2 -L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread -Lmbedtls/lib/ -llibmbedtls_SGX_u -lsgx_uae_service_simbecause I only wanted to linklibmbedtls_SGX_u.a. However, suprisingly, I am getting the error: "cannot find -llibmbedtls_SGX_u" even though I am very sure that "libmbedtls_SGX_u.a" is inside of the "mbedtls/lib" directory.
– Roymunson
Nov 12 '18 at 22:28
2
The command-lis peculiar. You have to specify the library name without the leadinglib. So it's just-lmbedtls_SGX_uinstead of-llibmbedtls_SGX_u. My initial answer was partially incorrect in that respect and you have probably been very quick in copying it.
– Codo
Nov 12 '18 at 22:32
Oh whoops, I thought you made a mistake by omitting the lib, so I left it in.
– Roymunson
Nov 12 '18 at 22:34
Where can I go to learn more about how to use the g++ compiler, so I can avoid making these mistakes in the future?
– Roymunson
Nov 12 '18 at 22:49
I think -pthread (not -lpthread).
– 2785528
Nov 12 '18 at 23:03
|
show 4 more comments
2
2
2
As has been mentioned in the comment, only specifying a directory with -L without specifying the name of a library in that directory is useless.
So you have to additionally specify the library names with -l.
So instead of:
g++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2
-L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread
-Lmbedtls/lib/
-lsgx_uae_service_sim
Use:
g++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2
-L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread
-Lmbedtls/lib/ -lmbedtls_SGX_t -lmbedtls_SGX_u
-lsgx_uae_service_sim
answered Nov 12 '18 at 22:21
Codo
50.5k11110148
As has been mentioned in the comment, only specifying a directory with -L without specifying the name of a library in that directory is useless.
So you have to additionally specify the library names with -l.
So instead of:
g++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2
-L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread
-Lmbedtls/lib/
-lsgx_uae_service_sim
Use:
g++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2
-L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread
-Lmbedtls/lib/ -lmbedtls_SGX_t -lmbedtls_SGX_u
-lsgx_uae_service_sim
answered Nov 12 '18 at 22:21
Codo
50.5k11110148
answered Nov 12 '18 at 22:21
Codo
50.5k11110148
answered Nov 12 '18 at 22:21
Codo
50.5k11110148
answered Nov 12 '18 at 22:21
Codo
50.5k11110148
50.5k11110148
I ran the commandg++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2 -L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread -Lmbedtls/lib/ -llibmbedtls_SGX_u -lsgx_uae_service_simbecause I only wanted to linklibmbedtls_SGX_u.a. However, suprisingly, I am getting the error: "cannot find -llibmbedtls_SGX_u" even though I am very sure that "libmbedtls_SGX_u.a" is inside of the "mbedtls/lib" directory.
– Roymunson
Nov 12 '18 at 22:28
2
The command-lis peculiar. You have to specify the library name without the leadinglib. So it's just-lmbedtls_SGX_uinstead of-llibmbedtls_SGX_u. My initial answer was partially incorrect in that respect and you have probably been very quick in copying it.
– Codo
Nov 12 '18 at 22:32
Oh whoops, I thought you made a mistake by omitting the lib, so I left it in.
– Roymunson
Nov 12 '18 at 22:34
Where can I go to learn more about how to use the g++ compiler, so I can avoid making these mistakes in the future?
– Roymunson
Nov 12 '18 at 22:49
I think -pthread (not -lpthread).
– 2785528
Nov 12 '18 at 23:03
|
show 4 more comments
I ran the commandg++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2 -L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread -Lmbedtls/lib/ -llibmbedtls_SGX_u -lsgx_uae_service_simbecause I only wanted to linklibmbedtls_SGX_u.a. However, suprisingly, I am getting the error: "cannot find -llibmbedtls_SGX_u" even though I am very sure that "libmbedtls_SGX_u.a" is inside of the "mbedtls/lib" directory.
– Roymunson
Nov 12 '18 at 22:28
2
The command-lis peculiar. You have to specify the library name without the leadinglib. So it's just-lmbedtls_SGX_uinstead of-llibmbedtls_SGX_u. My initial answer was partially incorrect in that respect and you have probably been very quick in copying it.
– Codo
Nov 12 '18 at 22:32
Oh whoops, I thought you made a mistake by omitting the lib, so I left it in.
– Roymunson
Nov 12 '18 at 22:34
Where can I go to learn more about how to use the g++ compiler, so I can avoid making these mistakes in the future?
– Roymunson
Nov 12 '18 at 22:49
I think -pthread (not -lpthread).
– 2785528
Nov 12 '18 at 23:03
I ran the command
g++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2 -L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread -Lmbedtls/lib/ -llibmbedtls_SGX_u -lsgx_uae_service_sim because I only wanted to link libmbedtls_SGX_u.a. However, suprisingly, I am getting the error: "cannot find -llibmbedtls_SGX_u" even though I am very sure that "libmbedtls_SGX_u.a" is inside of the "mbedtls/lib" directory.– Roymunson
Nov 12 '18 at 22:28
I ran the command
g++ App/Enclave_u.o App/App.o App/sgx_utils/sgx_utils.o -o app -m64 -O2 -L/opt/intel/sgxsdk/lib64 -lsgx_urts_sim -lpthread -Lmbedtls/lib/ -llibmbedtls_SGX_u -lsgx_uae_service_sim because I only wanted to link libmbedtls_SGX_u.a. However, suprisingly, I am getting the error: "cannot find -llibmbedtls_SGX_u" even though I am very sure that "libmbedtls_SGX_u.a" is inside of the "mbedtls/lib" directory.– Roymunson
Nov 12 '18 at 22:28
2
2
The command
-l is peculiar. You have to specify the library name without the leading lib. So it's just -lmbedtls_SGX_u instead of -llibmbedtls_SGX_u. My initial answer was partially incorrect in that respect and you have probably been very quick in copying it.– Codo
Nov 12 '18 at 22:32
The command
-l is peculiar. You have to specify the library name without the leading lib. So it's just -lmbedtls_SGX_u instead of -llibmbedtls_SGX_u. My initial answer was partially incorrect in that respect and you have probably been very quick in copying it.– Codo
Nov 12 '18 at 22:32
Oh whoops, I thought you made a mistake by omitting the lib, so I left it in.
– Roymunson
Nov 12 '18 at 22:34
Oh whoops, I thought you made a mistake by omitting the lib, so I left it in.
– Roymunson
Nov 12 '18 at 22:34
Where can I go to learn more about how to use the g++ compiler, so I can avoid making these mistakes in the future?
– Roymunson
Nov 12 '18 at 22:49
Where can I go to learn more about how to use the g++ compiler, so I can avoid making these mistakes in the future?
– Roymunson
Nov 12 '18 at 22:49
I think -pthread (not -lpthread).
– 2785528
Nov 12 '18 at 23:03
I think -pthread (not -lpthread).
– 2785528
Nov 12 '18 at 23:03
|
show 4 more comments
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3
-Ltells g++ where to look for.afiles, not to actually link them, you have to specify-llibmbedtls_SGX_u– orhtej2
Nov 12 '18 at 22:14
1
In general you should mention files referencing a symbol before the file providing the symbol. Many (not all, but most) linkers will discard any symbol that they have not seen a previous reference to.
– Jesper Juhl
Nov 12 '18 at 22:14
@JesperJuhl Can you explain what the implications of your statement are in terms of the commands I should be executing?
– Roymunson
Nov 12 '18 at 22:16
The implication is that whenever you tell your toolchain to link something you have to name the object files/libraries in an order where the ones that come first are the ones that consume/use symbols and the ones that provide the implementation come after.
– Jesper Juhl
Nov 12 '18 at 22:20
I think -pthread (not -lpthread).
– 2785528
Nov 12 '18 at 23:03