这只是关于同一问题的另一个线程。如何安装gem pg。我尝试了在stackoverflow上找到的几乎所有其他线程，但它不起作用。
我尝试通过 brew 和 dmg 包安装 postgress。结果是同样的错误。
Xcode Verion: 4.6
Rails Version: 4.0.0
Ruby Version: ruby-2.0.0-p247:
$ gcc --version
i686-apple-darwin11-llvm-gcc-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.11.00)
Copyright (C) 2007 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ gem install pg
Building native extensions. This could take a while...
ERROR: Error installing pg:
ERROR: Failed to build gem native extension.
/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/bin/ruby extconf.rb
checking for pg_config... yes
Using config values from /usr/bin/pg_config
checking for libpq-fe.h... yes
checking for libpq/libpq-fs.h... yes
checking for pg_config_manual.h... yes
checking for PQconnectdb() in -lpq... no
checking for PQconnectdb() in -llibpq... no
checking for PQconnectdb() in -lms/libpq... no
Can't find the PostgreSQL client library (libpq)
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers. Check the mkmf.log file for more details. You may
need configuration options.
Provided configuration options:
--with-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/bin/ruby
--with-pg
--without-pg
--with-pg-config
--without-pg-config
--with-pg_config
--without-pg_config
--with-pg-dir
--without-pg-dir
--with-pg-include
--without-pg-include=${pg-dir}/include
--with-pg-lib
--without-pg-lib=${pg-dir}/
--with-pqlib
--without-pqlib
--with-libpqlib
--without-libpqlib
--with-ms/libpqlib
--without-ms/libpqlib
Gem files will remain installed in /Users/arturo/.rvm/gems/ruby-2.0.0-p247/gems/pg-0.16.0 for inspection.
Results logged to /Users/arturo/.rvm/gems/ruby-2.0.0-p247/gems/pg-0.16.0/ext/gem_make.out
$ cat /Users/arturo/.rvm/gems/ruby-2.0.0-p247/gems/pg-0.16.0/ext/mkmf.log
find_executable: checking for pg_config... -------------------- yes
--------------------
"/usr/bin/clang -o conftest -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/x86_64-darwin11.4.2 -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/ruby/backward -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0 -I. -I/usr/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT -I/opt/local/include -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wunused-variable -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wshorten-64-to-32 -Wimplicit-function-declaration -fno-common -pipe conftest.c -L. -L/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/lib -L/usr/lib -L/opt/local/lib -L. -fstack-protector -L/usr/local/lib -L/opt/local/lib -lruby.2.0.0 -lpthread -ldl -lobjc "
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: int main(int argc, char **argv)
4: {
5: return 0;
6: }
/* end */
"/usr/bin/clang -o conftest -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/x86_64-darwin11.4.2 -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/ruby/backward -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0 -I. -I/usr/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT -I/opt/local/include -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wunused-variable -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wshorten-64-to-32 -Wimplicit-function-declaration -fno-common -pipe conftest.c -L. -L/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/lib -L/usr/lib -L/opt/local/lib -L. -fstack-protector -L/usr/local/lib -L/opt/local/lib -lruby.2.0.0 -Wl,-rpath,/usr/lib -lpthread -ldl -lobjc "
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: int main() {return 0;}
/* end */
find_header: checking for libpq-fe.h... -------------------- yes
"/usr/bin/clang -E -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/x86_64-darwin11.4.2 -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/ruby/backward -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0 -I. -I/usr/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT -I/opt/local/include -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wunused-variable -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wshorten-64-to-32 -Wimplicit-function-declaration -fno-common -pipe conftest.c -o conftest.i"
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <libpq-fe.h>
/* end */
--------------------
find_header: checking for libpq/libpq-fs.h... -------------------- yes
"/usr/bin/clang -E -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/x86_64-darwin11.4.2 -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/ruby/backward -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0 -I. -I/usr/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT -I/opt/local/include -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wunused-variable -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wshorten-64-to-32 -Wimplicit-function-declaration -fno-common -pipe conftest.c -o conftest.i"
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <libpq/libpq-fs.h>
/* end */
--------------------
find_header: checking for pg_config_manual.h... -------------------- yes
"/usr/bin/clang -E -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/x86_64-darwin11.4.2 -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/ruby/backward -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0 -I. -I/usr/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT -I/opt/local/include -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wunused-variable -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wshorten-64-to-32 -Wimplicit-function-declaration -fno-common -pipe conftest.c -o conftest.i"
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <pg_config_manual.h>
/* end */
--------------------
have_library: checking for PQconnectdb() in -lpq... -------------------- no
"/usr/bin/clang -o conftest -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/x86_64-darwin11.4.2 -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/ruby/backward -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0 -I. -I/usr/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT -I/opt/local/include -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wunused-variable -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wshorten-64-to-32 -Wimplicit-function-declaration -fno-common -pipe conftest.c -L. -L/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/lib -L/usr/lib -L/opt/local/lib -L. -fstack-protector -L/usr/local/lib -L/opt/local/lib -Wl,-rpath,/usr/lib -lruby.2.0.0 -lpq -lpthread -ldl -lobjc "
Undefined symbols for architecture x86_64:
"_CRYPTO_num_locks", referenced from:
_pqsecure_initialize in libpq.a(fe-secure.o)
"_CRYPTO_set_id_callback", referenced from:
_pqsecure_destroy in libpq.a(fe-secure.o)
_pqsecure_initialize in libpq.a(fe-secure.o)
"_CRYPTO_set_locking_callback", referenced from:
_pqsecure_destroy in libpq.a(fe-secure.o)
_pqsecure_initialize in libpq.a(fe-secure.o)
"_ENGINE_by_id", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_ENGINE_finish", referenced from:
_close_SSL in libpq.a(fe-secure.o)
_pqsecure_open_client in libpq.a(fe-secure.o)
"_ENGINE_free", referenced from:
_close_SSL in libpq.a(fe-secure.o)
_pqsecure_open_client in libpq.a(fe-secure.o)
"_ENGINE_init", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_ENGINE_load_private_key", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_ERR_get_error", referenced from:
_SSLerrmessage in libpq.a(fe-secure.o)
"_ERR_reason_error_string", referenced from:
_SSLerrmessage in libpq.a(fe-secure.o)
"_GSS_C_NT_HOSTBASED_SERVICE", referenced from:
_pg_fe_sendauth in libpq.a(fe-auth.o)
"_OPENSSL_config", referenced from:
_pqsecure_initialize in libpq.a(fe-secure.o)
"_SSL_CTX_ctrl", referenced from:
_pqsecure_initialize in libpq.a(fe-secure.o)
"_SSL_CTX_get_cert_store", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_SSL_CTX_load_verify_locations", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_SSL_CTX_new", referenced from:
_pqsecure_initialize in libpq.a(fe-secure.o)
"_SSL_CTX_use_certificate_chain_file", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_SSL_check_private_key", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_SSL_connect", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_SSL_free", referenced from:
_close_SSL in libpq.a(fe-secure.o)
"_SSL_get_error", referenced from:
_pqsecure_write in libpq.a(fe-secure.o)
_pqsecure_read in libpq.a(fe-secure.o)
_pqsecure_open_client in libpq.a(fe-secure.o)
"_SSL_get_peer_certificate", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_SSL_library_init", referenced from:
_pqsecure_initialize in libpq.a(fe-secure.o)
"_SSL_load_error_strings", referenced from:
_pqsecure_initialize in libpq.a(fe-secure.o)
"_SSL_new", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_SSL_pending", referenced from:
_pqSocketCheck in libpq.a(fe-misc.o)
"_SSL_read", referenced from:
_pqsecure_read in libpq.a(fe-secure.o)
"_SSL_set_ex_data", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_SSL_set_fd", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_SSL_set_verify", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_SSL_shutdown", referenced from:
_close_SSL in libpq.a(fe-secure.o)
"_SSL_use_PrivateKey", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_SSL_use_PrivateKey_file", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_SSL_use_certificate_file", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_SSL_write", referenced from:
_pqsecure_write in libpq.a(fe-secure.o)
"_TLSv1_method", referenced from:
_pqsecure_initialize in libpq.a(fe-secure.o)
"_X509_NAME_get_text_by_NID", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_X509_NAME_oneline", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_X509_STORE_load_locations", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_X509_STORE_set_flags", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_X509_free", referenced from:
_close_SSL in libpq.a(fe-secure.o)
"_X509_get_subject_name", referenced from:
_pqsecure_open_client in libpq.a(fe-secure.o)
"_error_message", referenced from:
_pg_fe_sendauth in libpq.a(fe-auth.o)
"_gss_delete_sec_context", referenced from:
_closePGconn in libpq.a(fe-connect.o)
_pg_GSS_continue in libpq.a(fe-auth.o)
"_gss_display_status", referenced from:
_pg_GSS_error_int in libpq.a(fe-auth.o)
"_gss_import_name", referenced from:
_pg_fe_sendauth in libpq.a(fe-auth.o)
"_gss_init_sec_context", referenced from:
_pg_GSS_continue in libpq.a(fe-auth.o)
"_gss_release_buffer", referenced from:
_closePGconn in libpq.a(fe-connect.o)
_pg_GSS_error_int in libpq.a(fe-auth.o)
_pg_GSS_continue in libpq.a(fe-auth.o)
"_gss_release_name", referenced from:
_closePGconn in libpq.a(fe-connect.o)
_pg_GSS_continue in libpq.a(fe-auth.o)
"_krb5_cc_close", referenced from:
_pg_fe_sendauth in libpq.a(fe-auth.o)
_pg_krb5_destroy in libpq.a(fe-auth.o)
"_krb5_cc_default", referenced from:
_pg_fe_sendauth in libpq.a(fe-auth.o)
"_krb5_cc_get_principal", referenced from:
_pg_fe_sendauth in libpq.a(fe-auth.o)
"_krb5_free_context", referenced from:
_pg_fe_sendauth in libpq.a(fe-auth.o)
_pg_krb5_destroy in libpq.a(fe-auth.o)
"_krb5_free_error", referenced from:
_pg_fe_sendauth in libpq.a(fe-auth.o)
"_krb5_free_principal", referenced from:
_pg_fe_sendauth in libpq.a(fe-auth.o)
_pg_krb5_destroy in libpq.a(fe-auth.o)
"_krb5_free_unparsed_name", referenced from:
_pg_krb5_destroy in libpq.a(fe-auth.o)
"_krb5_init_context", referenced from:
_pg_fe_sendauth in libpq.a(fe-auth.o)
"_krb5_sendauth", referenced from:
_pg_fe_sendauth in libpq.a(fe-auth.o)
"_krb5_sname_to_principal", referenced from:
_pg_fe_sendauth in libpq.a(fe-auth.o)
"_krb5_unparse_name", referenced from:
_pg_fe_sendauth in libpq.a(fe-auth.o)
"_ldap_count_entries", referenced from:
_parseServiceFile in libpq.a(fe-connect.o)
"_ldap_err2string", referenced from:
_parseServiceFile in libpq.a(fe-connect.o)
"_ldap_first_entry", referenced from:
_parseServiceFile in libpq.a(fe-connect.o)
"_ldap_get_values_len", referenced from:
_parseServiceFile in libpq.a(fe-connect.o)
"_ldap_init", referenced from:
_parseServiceFile in libpq.a(fe-connect.o)
"_ldap_msgfree", referenced from:
_parseServiceFile in libpq.a(fe-connect.o)
"_ldap_result", referenced from:
_parseServiceFile in libpq.a(fe-connect.o)
"_ldap_search_st", referenced from:
_parseServiceFile in libpq.a(fe-connect.o)
"_ldap_simple_bind", referenced from:
_parseServiceFile in libpq.a(fe-connect.o)
"_ldap_unbind", referenced from:
_parseServiceFile in libpq.a(fe-connect.o)
"_ldap_value_free_len", referenced from:
_parseServiceFile in libpq.a(fe-connect.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <libpq-fe.h>
4:
5: /*top*/
6: extern int t(void);
7: int t(void) { void ((*volatile p)()); p = (void ((*)()))PQconnectdb; return 0; }
8: int main(int argc, char **argv)
9: {
10: if (argc > 1000000) {
11: printf("%p", &t);
12: }
13:
14: return 0;
15: }
/* end */
"/usr/bin/clang -o conftest -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/x86_64-darwin11.4.2 -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/ruby/backward -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0 -I. -I/usr/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT -I/opt/local/include -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wunused-variable -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wshorten-64-to-32 -Wimplicit-function-declaration -fno-common -pipe conftest.c -L. -L/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/lib -L/usr/lib -L/opt/local/lib -L. -fstack-protector -L/usr/local/lib -L/opt/local/lib -Wl,-rpath,/usr/lib -lruby.2.0.0 -lpq -lpthread -ldl -lobjc "
conftest.c:7:27: error: too few arguments to function call, single argument 'conninfo' was not specified
int t(void) { PQconnectdb(); return 0; }
~~~~~~~~~~~ ^
/usr/include/libpq-fe.h:234:1: note: 'PQconnectdb' declared here
extern PGconn *PQconnectdb(const char *conninfo);
^
1 error generated.
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <libpq-fe.h>
4:
5: /*top*/
6: extern int t(void);
7: int t(void) { PQconnectdb(); return 0; }
8: int main(int argc, char **argv)
9: {
10: if (argc > 1000000) {
11: printf("%p", &t);
12: }
13:
14: return 0;
15: }
/* end */
--------------------
have_library: checking for PQconnectdb() in -llibpq... -------------------- no
"/usr/bin/clang -o conftest -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/x86_64-darwin11.4.2 -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/ruby/backward -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0 -I. -I/usr/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT -I/opt/local/include -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wunused-variable -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wshorten-64-to-32 -Wimplicit-function-declaration -fno-common -pipe conftest.c -L. -L/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/lib -L/usr/lib -L/opt/local/lib -L. -fstack-protector -L/usr/local/lib -L/opt/local/lib -Wl,-rpath,/usr/lib -lruby.2.0.0 -llibpq -lpthread -ldl -lobjc "
ld: library not found for -llibpq
clang: error: linker command failed with exit code 1 (use -v to see invocation)
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <libpq-fe.h>
4:
5: /*top*/
6: extern int t(void);
7: int t(void) { void ((*volatile p)()); p = (void ((*)()))PQconnectdb; return 0; }
8: int main(int argc, char **argv)
9: {
10: if (argc > 1000000) {
11: printf("%p", &t);
12: }
13:
14: return 0;
15: }
/* end */
"/usr/bin/clang -o conftest -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/x86_64-darwin11.4.2 -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/ruby/backward -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0 -I. -I/usr/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT -I/opt/local/include -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wunused-variable -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wshorten-64-to-32 -Wimplicit-function-declaration -fno-common -pipe conftest.c -L. -L/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/lib -L/usr/lib -L/opt/local/lib -L. -fstack-protector -L/usr/local/lib -L/opt/local/lib -Wl,-rpath,/usr/lib -lruby.2.0.0 -llibpq -lpthread -ldl -lobjc "
conftest.c:7:27: error: too few arguments to function call, single argument 'conninfo' was not specified
int t(void) { PQconnectdb(); return 0; }
~~~~~~~~~~~ ^
/usr/include/libpq-fe.h:234:1: note: 'PQconnectdb' declared here
extern PGconn *PQconnectdb(const char *conninfo);
^
1 error generated.
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <libpq-fe.h>
4:
5: /*top*/
6: extern int t(void);
7: int t(void) { PQconnectdb(); return 0; }
8: int main(int argc, char **argv)
9: {
10: if (argc > 1000000) {
11: printf("%p", &t);
12: }
13:
14: return 0;
15: }
/* end */
--------------------
have_library: checking for PQconnectdb() in -lms/libpq... -------------------- no
"/usr/bin/clang -o conftest -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/x86_64-darwin11.4.2 -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/ruby/backward -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0 -I. -I/usr/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT -I/opt/local/include -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wunused-variable -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wshorten-64-to-32 -Wimplicit-function-declaration -fno-common -pipe conftest.c -L. -L/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/lib -L/usr/lib -L/opt/local/lib -L. -fstack-protector -L/usr/local/lib -L/opt/local/lib -Wl,-rpath,/usr/lib -lruby.2.0.0 -lms/libpq -lpthread -ldl -lobjc "
ld: library not found for -lms/libpq
clang: error: linker command failed with exit code 1 (use -v to see invocation)
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <libpq-fe.h>
4:
5: /*top*/
6: extern int t(void);
7: int t(void) { void ((*volatile p)()); p = (void ((*)()))PQconnectdb; return 0; }
8: int main(int argc, char **argv)
9: {
10: if (argc > 1000000) {
11: printf("%p", &t);
12: }
13:
14: return 0;
15: }
/* end */
"/usr/bin/clang -o conftest -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/x86_64-darwin11.4.2 -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0/ruby/backward -I/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/include/ruby-2.0.0 -I. -I/usr/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT -I/opt/local/include -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wunused-variable -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wshorten-64-to-32 -Wimplicit-function-declaration -fno-common -pipe conftest.c -L. -L/Users/arturo/.rvm/rubies/ruby-2.0.0-p247/lib -L/usr/lib -L/opt/local/lib -L. -fstack-protector -L/usr/local/lib -L/opt/local/lib -Wl,-rpath,/usr/lib -lruby.2.0.0 -lms/libpq -lpthread -ldl -lobjc "
conftest.c:7:27: error: too few arguments to function call, single argument 'conninfo' was not specified
int t(void) { PQconnectdb(); return 0; }
~~~~~~~~~~~ ^
/usr/include/libpq-fe.h:234:1: note: 'PQconnectdb' declared here
extern PGconn *PQconnectdb(const char *conninfo);
^
1 error generated.
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <libpq-fe.h>
4:
5: /*top*/
6: extern int t(void);
7: int t(void) { PQconnectdb(); return 0; }
8: int main(int argc, char **argv)
9: {
10: if (argc > 1000000) {
11: printf("%p", &t);
12: }
13:
14: return 0;
15: }
/* end */
--------------------
提前致谢
解决方案 以下解决方案适用于 mac 上的 mysql 和 postgresql gems。
确保已安装 xcode + 命令行工具。
就我而言，我删除了 mysql 和 postgresql 以前的安装。我还删除了 rvm 及其 ruby 版本。（不要删除 MAC 自带的 Ruby）
如果已安装，请卸载 brew。
再次安装 brew。
运行 $ brew doctor
修复来自 brew doctor 的所有警告。
运行： brew install postgresql
运行： brew install mysql
安装 rvm
运行 rvm 要求并修复任何问题。
通过 rvm 安装 ruby
运行 gem install 'pg'
运行 gem install 'mysql2'
一切都很好（Y）