Openssllibcrypto. a and libssl. a solve the problem of undefined reference to error when referencing openssl static libraries libcrypto..

Openssllibcrypto. a and libssl. a solve the problem of undefined reference to error when referencing openssl static libraries libcrypto..

Recently, the project that uses openssl to link http and https has encountered the following problems during compilation.

/Usr/local/openssl/lib/libcrypto. a (async. o): In function 'async _ free_pool_internal ':
Async. c :(. text + 0xe4): undefined reference to 'pthread _ setspecific'
Async. c :(. text + 0xf4): undefined reference to 'pthread _ getspecific'
Async. c :(. text + 0x104): undefined reference to 'pthread _ setspecific'
/Usr/local/openssl/lib/libcrypto. a (async. o): In function 'async _ init_thread.part.1 ':
Async. c :(. text + 0x253): undefined reference to 'pthread _ setspecific'
/Usr/local/openssl/lib/libcrypto. a (async. o): In function 'async _ start_func ':
Async. c :(. text + 0x36f): undefined reference to 'pthread _ getspecific'
Async. c :(. text + 0x39e): undefined reference to 'pthread _ getspecific'
/Usr/local/openssl/lib/libcrypto. a (async. o): In function 'async _ start_job ':
Async. c :(. text + 0x404): undefined reference to 'pthread _ getspecific'
Async. c :(. text + 0x41e): undefined reference to 'pthread _ getspecific'
Async. c :(. text + 0x433): undefined reference to 'pthread _ getspecific'
/Usr/local/openssl/lib/libcrypto. a (async. o): async. c :(. text + 0x44c): more undefined references to 'pthread _ getspecific 'follow
/Usr/local/openssl/lib/libcrypto. a (async. o): In function 'async _ start_job ':
Async. c :(. text + 0x7ef): undefined reference to 'pthread _ setspecific'
Async. c :(. text + 0x811): undefined reference to 'pthread _ getspecific'
Async. c :(. text + 0x82d): undefined reference to 'pthread _ getspecific'
Async. c :(. text + 0x83f): undefined reference to 'pthread _ getspecific'
Async. c :(. text + 0x870): undefined reference to 'pthread _ getspecific'
Async. c :(. text + 0x891): undefined reference to 'pthread _ getspecific'
/Usr/local/openssl/lib/libcrypto. a (async. o): async. c :(. text + 0x8a6): more undefined references to 'pthread _ getspecific 'follow
/Usr/local/openssl/lib/libcrypto. a (async_posix.o): In function 'async _ global_init ':
Async_posix.c :(. text + 0xc): undefined reference to 'pthread _ key_create'
Async_posix.c :(. text + 0x1e): undefined reference to 'pthread _ key_create'
/Usr/local/openssl/lib/libcrypto. a (async_posix.o): In function 'async _ local_init ':
Async_posix.c :(. text + 0x3d): undefined reference to 'pthread _ setspecific'
Async_posix.c :(. text + 0x50): undefined reference to 'pthread _ setspecific'
/Usr/local/openssl/lib/libcrypto. a (dso_dlfcn.o): In function 'dlfcn _ globallookup ':
Dso_dlfcn.c :(. text + 0x21): undefined reference to 'dlopen'
Dso_dlfcn.c :(. text + 0x34): undefined reference to 'dlsym'
Dso_dlfcn.c :(. text + 0x3f): undefined reference to 'dlclose'
/Usr/local/openssl/lib/libcrypto. a (dso_dlfcn.o): In function 'dlfcn _ bind_func ':
Dso_dlfcn.c :(. text + 0x354): undefined reference to 'dlsym'
Dso_dlfcn.c :(. text + 0x3fb): undefined reference to 'dlerror'
/Usr/local/openssl/lib/libcrypto. a (dso_dlfcn.o): In function 'dlfcn _ bind_var ':
Dso_dlfcn.c :(. text + 0x474): undefined reference to 'dlsym'
Dso_dlfcn.c :(. text + 0x52e): undefined reference to 'dlerror'
/Usr/local/openssl/lib/libcrypto. a (dso_dlfcn.o): In function 'dlfcn _ load ':
Dso_dlfcn.c :(. text + 0x5a4): undefined reference to 'dlopen'
Dso_dlfcn.c :(. text + 0x60b): undefined reference to 'dlclose'
Dso_dlfcn.c :(. text + 0x638): undefined reference to 'dlerror'
/Usr/local/openssl/lib/libcrypto. a (dso_dlfcn.o): In function 'dlfcn _ pathbyaddr ':
Dso_dlfcn.c :(. text + 0x6ce): undefined reference to 'dladd'
Dso_dlfcn.c :(. text + 0x731): undefined reference to 'dlerror'
/Usr/local/openssl/lib/libcrypto. a (dso_dlfcn.o): In function 'dlfcn _ unload ':
Dso_dlfcn.c :(. text + 0x78a): undefined reference to 'dlclose'

 

Solution:

Gcc obj/Debug/main. o-L/usr/local/openssl/lib-lssl-lcrypto-ldl-lpthread-o main

Cause analysis:

When linking this database, you must pay attention to two issues:

1. For openssl library version problems, please link directly to the openssl library path you need. For example, my files are/usr/local/openssl/lib,

2. Note that-lssl-lcrypto must be written before-ldl-lpthread.

Related Knowledge:

-L: This option specifies the folder address of the Linked Library.

-L (lower-case L):-lssl is the library libssl. a under the/usr/local/openssl/lib directory. The Compiler automatically searches for libssl. a or libssl. so.

-I (uppercase I): Specifies the folder address of the header file.