LD_LIBRARY_PATH=.:/usr/local/lib pkg-config --exists yaml-0.1 LD_LIBRARY_PATH=.:/usr/local/lib pkg-config --libs yaml-0.1 | => "-lyaml\n" LD_LIBRARY_PATH=.:/usr/local/lib "gcc -o conftest -I/usr/local/include/ruby-3.1.0/x86_64-linux -I/usr/local/include/ruby-3.1.0/ruby/backward -I/usr/local/include/ruby-3.1.0 -I. -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wdeprecated-declarations -Wduplicated-cond -Wimplicit-function-declaration -Wimplicit-int -Wmisleading-indentation -Wpointer-arith -Wwrite-strings -Wold-style-definition -Wimplicit-fallthrough=0 -Wmissing-noreturn -Wno-cast-function-type -Wno-constant-logical-operand -Wno-long-long -Wno-missing-field-initializers -Wno-overlength-strings -Wno-packed-bitfield-compat -Wno-parentheses-equality -Wno-self-assign -Wno-tautological-compare -Wno-unused-parameter -Wno-unused-value -Wsuggest-attribute=format -Wsuggest-attribute=noreturn -Wunused-variable -Wundef -fPIC conftest.c -L. -L/usr/local/lib -Wl,-rpath,/usr/local/lib -L. -fstack-protector-strong -rdynamic -Wl,-export-dynamic -Wl,--no-as-needed -Wl,-rpath,/usr/local/lib -L/usr/local/lib -lruby -lm -lc" checked program was: /* begin */ 1: #include "ruby.h" 2: 3: int main(int argc, char **argv) 4: { 5: return !!argv[argc]; 6: } /* end */ LD_LIBRARY_PATH=.:/usr/local/lib "gcc -o conftest -I/usr/local/include/ruby-3.1.0/x86_64-linux -I/usr/local/include/ruby-3.1.0/ruby/backward -I/usr/local/include/ruby-3.1.0 -I. -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wdeprecated-declarations -Wduplicated-cond -Wimplicit-function-declaration -Wimplicit-int -Wmisleading-indentation -Wpointer-arith -Wwrite-strings -Wold-style-definition -Wimplicit-fallthrough=0 -Wmissing-noreturn -Wno-cast-function-type -Wno-constant-logical-operand -Wno-long-long -Wno-missing-field-initializers -Wno-overlength-strings -Wno-packed-bitfield-compat -Wno-parentheses-equality -Wno-self-assign -Wno-tautological-compare -Wno-unused-parameter -Wno-unused-value -Wsuggest-attribute=format -Wsuggest-attribute=noreturn -Wunused-variable -Wundef -fPIC conftest.c -L. -L/usr/local/lib -Wl,-rpath,/usr/local/lib -L. -fstack-protector-strong -rdynamic -Wl,-export-dynamic -Wl,--no-as-needed -Wl,-rpath,/usr/local/lib -L/usr/local/lib -lruby -lyaml -lm -lc" checked program was: /* begin */ 1: #include "ruby.h" 2: 3: int main(int argc, char **argv) 4: { 5: return !!argv[argc]; 6: } /* end */ LD_LIBRARY_PATH=.:/usr/local/lib pkg-config --cflags-only-I yaml-0.1 | => "\n" LD_LIBRARY_PATH=.:/usr/local/lib pkg-config --cflags-only-other yaml-0.1 | => "\n" LD_LIBRARY_PATH=.:/usr/local/lib pkg-config --libs-only-l yaml-0.1 | => "-lyaml\n" package configuration for yaml-0.1 incflags: cflags: ldflags: libs: -lyaml find_header: checking for yaml.h... -------------------- yes LD_LIBRARY_PATH=.:/usr/local/lib "gcc -I/usr/local/include/ruby-3.1.0/x86_64-linux -I/usr/local/include/ruby-3.1.0/ruby/backward -I/usr/local/include/ruby-3.1.0 -I. -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wdeprecated-declarations -Wduplicated-cond -Wimplicit-function-declaration -Wimplicit-int -Wmisleading-indentation -Wpointer-arith -Wwrite-strings -Wold-style-definition -Wimplicit-fallthrough=0 -Wmissing-noreturn -Wno-cast-function-type -Wno-constant-logical-operand -Wno-long-long -Wno-missing-field-initializers -Wno-overlength-strings -Wno-packed-bitfield-compat -Wno-parentheses-equality -Wno-self-assign -Wno-tautological-compare -Wno-unused-parameter -Wno-unused-value -Wsuggest-attribute=format -Wsuggest-attribute=noreturn -Wunused-variable -Wundef -fPIC -c conftest.c" checked program was: /* begin */ 1: #include "ruby.h" 2: 3: #include /* end */ -------------------- find_library: checking for yaml_get_version() in -lyaml... -------------------- yes LD_LIBRARY_PATH=.:/usr/local/lib "gcc -o conftest -I/usr/local/include/ruby-3.1.0/x86_64-linux -I/usr/local/include/ruby-3.1.0/ruby/backward -I/usr/local/include/ruby-3.1.0 -I. -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wdeprecated-declarations -Wduplicated-cond -Wimplicit-function-declaration -Wimplicit-int -Wmisleading-indentation -Wpointer-arith -Wwrite-strings -Wold-style-definition -Wimplicit-fallthrough=0 -Wmissing-noreturn -Wno-cast-function-type -Wno-constant-logical-operand -Wno-long-long -Wno-missing-field-initializers -Wno-overlength-strings -Wno-packed-bitfield-compat -Wno-parentheses-equality -Wno-self-assign -Wno-tautological-compare -Wno-unused-parameter -Wno-unused-value -Wsuggest-attribute=format -Wsuggest-attribute=noreturn -Wunused-variable -Wundef -fPIC conftest.c -L. -L/usr/local/lib -Wl,-rpath,/usr/local/lib -L. -fstack-protector-strong -rdynamic -Wl,-export-dynamic -Wl,--no-as-needed -lyaml -Wl,-rpath,/usr/local/lib -L/usr/local/lib -lruby -lyaml -lyaml -lm -lc" conftest.c: In function ‘t’: conftest.c:14:57: error: ‘yaml_get_version’ undeclared (first use in this function) 14 | int t(void) { void ((*volatile p)()); p = (void ((*)()))yaml_get_version; return !p; } | ^~~~~~~~~~~~~~~~ conftest.c:14:57: note: each undeclared identifier is reported only once for each function it appears in conftest.c: At top level: cc1: note: unrecognized command-line option ‘-Wno-self-assign’ may have been intended to silence earlier diagnostics cc1: note: unrecognized command-line option ‘-Wno-parentheses-equality’ may have been intended to silence earlier diagnostics cc1: note: unrecognized command-line option ‘-Wno-constant-logical-operand’ may have been intended to silence earlier diagnostics checked program was: /* begin */ 1: #include "ruby.h" 2: 3: /*top*/ 4: extern int t(void); 5: int main(int argc, char **argv) 6: { 7: if (argc > 1000000) { 8: int (* volatile tp)(void)=(int (*)(void))&t; 9: printf("%d", (*tp)()); 10: } 11: 12: return !!argv[argc]; 13: } 14: int t(void) { void ((*volatile p)()); p = (void ((*)()))yaml_get_version; return !p; } /* end */ LD_LIBRARY_PATH=.:/usr/local/lib "gcc -o conftest -I/usr/local/include/ruby-3.1.0/x86_64-linux -I/usr/local/include/ruby-3.1.0/ruby/backward -I/usr/local/include/ruby-3.1.0 -I. -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wdeprecated-declarations -Wduplicated-cond -Wimplicit-function-declaration -Wimplicit-int -Wmisleading-indentation -Wpointer-arith -Wwrite-strings -Wold-style-definition -Wimplicit-fallthrough=0 -Wmissing-noreturn -Wno-cast-function-type -Wno-constant-logical-operand -Wno-long-long -Wno-missing-field-initializers -Wno-overlength-strings -Wno-packed-bitfield-compat -Wno-parentheses-equality -Wno-self-assign -Wno-tautological-compare -Wno-unused-parameter -Wno-unused-value -Wsuggest-attribute=format -Wsuggest-attribute=noreturn -Wunused-variable -Wundef -fPIC conftest.c -L. -L/usr/local/lib -Wl,-rpath,/usr/local/lib -L. -fstack-protector-strong -rdynamic -Wl,-export-dynamic -Wl,--no-as-needed -lyaml -Wl,-rpath,/usr/local/lib -L/usr/local/lib -lruby -lyaml -lyaml -lm -lc" checked program was: /* begin */ 1: #include "ruby.h" 2: 3: /*top*/ 4: extern int t(void); 5: int main(int argc, char **argv) 6: { 7: if (argc > 1000000) { 8: int (* volatile tp)(void)=(int (*)(void))&t; 9: printf("%d", (*tp)()); 10: } 11: 12: return !!argv[argc]; 13: } 14: extern void yaml_get_version(); 15: int t(void) { yaml_get_version(); return 0; } /* end */ --------------------