diff --git a/action.yml b/action.yml
index afc63d5..3b66cd6 100644
--- a/action.yml
+++ b/action.yml
@@ -9,7 +9,7 @@ runs:
   using: "composite"
   steps:
     - run: |
-        curl -OL https://github.com/casadi/mockups/releases/download/v41/mockups_${{ inputs.tag }}.zip
+        curl -OL https://github.com/casadi/mockups/releases/download/v43/mockups_${{ inputs.tag }}.zip
         unzip mockups_${{ inputs.tag }}.zip -d mockups
         ls mockups
         ls mockups/cmake
diff --git a/cplex/generate.py b/cplex/generate.py
index 37a0f5d..46b8582 100644
--- a/cplex/generate.py
+++ b/cplex/generate.py
@@ -57,6 +57,21 @@ def function_ptr(decl):
 
   fout.write("""
   
+  #if defined(_WIN32)
+  static HINSTANCE h;
+  #else
+  void * h;
+  #endif
+  
+  void cplex_adaptor_unload() {
+    if (h) {
+        #if defined(_WIN32)
+        FreeLibray(h);
+        #elif defined(__APPLE__)
+        dlclose(h);
+        #endif
+    }
+  }
   int cplex_adaptor_load(char* err_msg, unsigned int err_msg_len) {
   
     const char* suffix = getenv("CPLEX_VERSION");
@@ -84,11 +99,11 @@ def function_ptr(decl):
     snprintf(buffer, 100, "libcplex%s.%s", suffix, library_suffix);
 
     #if defined(_WIN32)
-    HINSTANCE h = LoadLibrary(TEXT(buffer));
+    h = LoadLibrary(TEXT(buffer));
     #elif defined(__APPLE__)
-    void * h = dlopen(buffer, RTLD_LAZY | RTLD_LOCAL);
+    h = dlopen(buffer, RTLD_LAZY | RTLD_LOCAL);
     #else
-    void * h = dlopen(buffer, RTLD_LAZY | RTLD_LOCAL | RTLD_DEEPBIND);
+    h = dlopen(buffer, RTLD_LAZY | RTLD_LOCAL | RTLD_DEEPBIND);
     #endif
     
     if (h) {
@@ -98,10 +113,12 @@ def function_ptr(decl):
   fout.write("""#if CPX_APIMODEL == CPX_APIMODEL_LARGE\n""")
   for decl in method_declarations:
     fout.write("""            %s = (%s) GetProcAddress(h, "%s");\n""" % (get_name(decl),function_ptr(decl),get_name(decl).replace("CPXX","CPXL")))
+    fout.write("""            if (%s==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol '%s' in libcplex%%s.%%s", suffix, library_suffix); return 2; };\n""" % (get_name(decl),get_name(decl).replace("CPXX","CPXL")))
   fout.write("""#endif\n""")
   fout.write("""#if CPX_APIMODEL == CPX_APIMODEL_SMALL\n""")
   for decl in method_declarations:
     fout.write("""            %s = (%s) GetProcAddress(h, "%s");\n""" % (get_name(decl),function_ptr(decl),get_name(decl).replace("CPXX","CPXS")))
+    fout.write("""            if (%s==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol '%s' in libcplex%%s.%%s", suffix, library_suffix); return 2; };\n""" % (get_name(decl),get_name(decl).replace("CPXX","CPXS")))
   fout.write("""#endif\n""")
   
   fout.write("""
@@ -111,10 +128,12 @@ def function_ptr(decl):
   fout.write("""#if CPX_APIMODEL == CPX_APIMODEL_LARGE\n""")
   for decl in method_declarations:
     fout.write("""            %s = (%s) dlsym(h, "%s");\n""" % (get_name(decl),function_ptr(decl),get_name(decl).replace("CPXX","CPXL")))
+    fout.write("""            if (%s==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol '%s' in libcplex%%s.%%s", suffix, library_suffix); return 2; };\n""" % (get_name(decl),get_name(decl).replace("CPXX","CPXL")))
   fout.write("""#endif\n""")
   fout.write("""#if CPX_APIMODEL == CPX_APIMODEL_SMALL\n""")
   for decl in method_declarations:
     fout.write("""            %s = (%s) dlsym(h, "%s");\n""" % (get_name(decl),function_ptr(decl),get_name(decl).replace("CPXX","CPXS")))
+    fout.write("""            if (%s==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol '%s' in libcplex%%s.%%s", suffix, library_suffix); return 2; };\n""" % (get_name(decl),get_name(decl).replace("CPXX","CPXS")))
   fout.write("""#endif\n""")                 
   fout.write("""
       #endif // _WIN32
diff --git a/cplex/include/cplex.h b/cplex/include/cplex.h
index 7f741c1..6cdae24 100644
--- a/cplex/include/cplex.h
+++ b/cplex/include/cplex.h
@@ -141,6 +141,7 @@ typedef void       *CPXVOIDptr;
 #endif
 
 int cplex_adaptor_load(char* err_msg, unsigned int err_msg_len);
+void cplex_adaptor_unload();
 
 #define CPXXaddmipstarts adaptor_CPXXaddmipstarts
 DLLSYMBOL int (*CPXXaddmipstarts)(CPXCENVptr, CPXLPptr, int, CPXNNZ, CPXNNZ const *, CPXDIM const *, double const *, int const *, char const *const *);
diff --git a/cplex/include/cplex.h.in b/cplex/include/cplex.h.in
index 77d2af8..b75529d 100644
--- a/cplex/include/cplex.h.in
+++ b/cplex/include/cplex.h.in
@@ -141,6 +141,7 @@ typedef void       *CPXVOIDptr;
 #endif
 
 int cplex_adaptor_load(char* err_msg, unsigned int err_msg_len);
+void cplex_adaptor_unload();
 
 [cplex_core.h]
 
diff --git a/cplex/src/cplex.c b/cplex/src/cplex.c
index eeb89a1..a07800c 100644
--- a/cplex/src/cplex.c
+++ b/cplex/src/cplex.c
@@ -48,6 +48,21 @@ int (*CPXXsolution)(CPXCENVptr, CPXCLPptr, int *, double *, double *, double *,
 int (*CPXXwriteprob)(CPXCENVptr, CPXCLPptr, char const *, char const *) = NULL;
 
   
+  #if defined(_WIN32)
+  static HINSTANCE h;
+  #else
+  void * h;
+  #endif
+  
+  void cplex_adaptor_unload() {
+    if (h) {
+        #if defined(_WIN32)
+        FreeLibray(h);
+        #elif defined(__APPLE__)
+        dlclose(h);
+        #endif
+    }
+  }
   int cplex_adaptor_load(char* err_msg, unsigned int err_msg_len) {
   
     const char* suffix = getenv("CPLEX_VERSION");
@@ -75,160 +90,296 @@ int (*CPXXwriteprob)(CPXCENVptr, CPXCLPptr, char const *, char const *) = NULL;
     snprintf(buffer, 100, "libcplex%s.%s", suffix, library_suffix);
 
     #if defined(_WIN32)
-    HINSTANCE h = LoadLibrary(TEXT(buffer));
+    h = LoadLibrary(TEXT(buffer));
     #elif defined(__APPLE__)
-    void * h = dlopen(buffer, RTLD_LAZY | RTLD_LOCAL);
+    h = dlopen(buffer, RTLD_LAZY | RTLD_LOCAL);
     #else
-    void * h = dlopen(buffer, RTLD_LAZY | RTLD_LOCAL | RTLD_DEEPBIND);
+    h = dlopen(buffer, RTLD_LAZY | RTLD_LOCAL | RTLD_DEEPBIND);
     #endif
     
     if (h) {
       #ifdef _WIN32
 #if CPX_APIMODEL == CPX_APIMODEL_LARGE
             CPXXaddmipstarts = (int (*)(CPXCENVptr, CPXLPptr, int, CPXNNZ, CPXNNZ const *, CPXDIM const *, double const *, int const *, char const *const *)) GetProcAddress(h, "CPXLaddmipstarts");
+            if (CPXXaddmipstarts==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLaddmipstarts' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXaddqconstr = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, CPXNNZ, double, int, CPXDIM const *, double const *, CPXDIM const *, CPXDIM const *, double const *, char const *)) GetProcAddress(h, "CPXLaddqconstr");
+            if (CPXXaddqconstr==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLaddqconstr' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXaddrows = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, CPXDIM, CPXNNZ, double const *, char const *, CPXNNZ const *, CPXDIM const *, double const *, char const *const *, char const *const *)) GetProcAddress(h, "CPXLaddrows");
+            if (CPXXaddrows==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLaddrows' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXaddsos = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, CPXNNZ, char const *, CPXNNZ const *, CPXDIM const *, double const *, char const *const *)) GetProcAddress(h, "CPXLaddsos");
+            if (CPXXaddsos==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLaddsos' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcloseCPLEX = (int (*)(CPXENVptr *)) GetProcAddress(h, "CPXLcloseCPLEX");
+            if (CPXXcloseCPLEX==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLcloseCPLEX' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcopyctype = (int (*)(CPXCENVptr, CPXLPptr, char const *)) GetProcAddress(h, "CPXLcopyctype");
+            if (CPXXcopyctype==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLcopyctype' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcopylp = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, CPXDIM, int, double const *, double const *, char const *, CPXNNZ const *, CPXDIM const *, CPXDIM const *, double const *, double const *, double const *, double const *)) GetProcAddress(h, "CPXLcopylp");
+            if (CPXXcopylp==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLcopylp' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcopyquad = (int (*)(CPXCENVptr, CPXLPptr, CPXNNZ const *, CPXDIM const *, CPXDIM const *, double const *)) GetProcAddress(h, "CPXLcopyquad");
+            if (CPXXcopyquad==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLcopyquad' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcopystart = (int (*)(CPXCENVptr, CPXLPptr, int const *, int const *, double const *, double const *, double const *, double const *)) GetProcAddress(h, "CPXLcopystart");
+            if (CPXXcopystart==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLcopystart' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcreateprob = (CPXLPptr (*)(CPXCENVptr, int *, char const *)) GetProcAddress(h, "CPXLcreateprob");
+            if (CPXXcreateprob==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLcreateprob' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXfreeprob = (int (*)(CPXCENVptr, CPXLPptr *)) GetProcAddress(h, "CPXLfreeprob");
+            if (CPXXfreeprob==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLfreeprob' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetbase = (int (*)(CPXCENVptr, CPXCLPptr, int *, int *)) GetProcAddress(h, "CPXLgetbase");
+            if (CPXXgetbase==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetbase' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgeterrorstring = (CPXCCHARptr (*)(CPXCENVptr, int, char *)) GetProcAddress(h, "CPXLgeterrorstring");
+            if (CPXXgeterrorstring==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgeterrorstring' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetnumcols = (CPXDIM (*)(CPXCENVptr, CPXCLPptr)) GetProcAddress(h, "CPXLgetnumcols");
+            if (CPXXgetnumcols==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetnumcols' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetnumrows = (CPXDIM (*)(CPXCENVptr, CPXCLPptr)) GetProcAddress(h, "CPXLgetnumrows");
+            if (CPXXgetnumrows==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetnumrows' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetobjval = (int (*)(CPXCENVptr, CPXCLPptr, double *)) GetProcAddress(h, "CPXLgetobjval");
+            if (CPXXgetobjval==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetobjval' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetparamnum = (int (*)(CPXCENVptr, char const *, int *)) GetProcAddress(h, "CPXLgetparamnum");
+            if (CPXXgetparamnum==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetparamnum' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetparamtype = (int (*)(CPXCENVptr, int, int *)) GetProcAddress(h, "CPXLgetparamtype");
+            if (CPXXgetparamtype==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetparamtype' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetprobtype = (int (*)(CPXCENVptr, CPXCLPptr)) GetProcAddress(h, "CPXLgetprobtype");
+            if (CPXXgetprobtype==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetprobtype' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetslack = (int (*)(CPXCENVptr, CPXCLPptr, double *, CPXDIM, CPXDIM)) GetProcAddress(h, "CPXLgetslack");
+            if (CPXXgetslack==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetslack' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetstat = (int (*)(CPXCENVptr, CPXCLPptr)) GetProcAddress(h, "CPXLgetstat");
+            if (CPXXgetstat==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetstat' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetstatstring = (CPXCHARptr (*)(CPXCENVptr, int, char *)) GetProcAddress(h, "CPXLgetstatstring");
+            if (CPXXgetstatstring==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetstatstring' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetx = (int (*)(CPXCENVptr, CPXCLPptr, double *, CPXDIM, CPXDIM)) GetProcAddress(h, "CPXLgetx");
+            if (CPXXgetx==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetx' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXmipopt = (int (*)(CPXCENVptr, CPXLPptr)) GetProcAddress(h, "CPXLmipopt");
+            if (CPXXmipopt==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLmipopt' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXnewcols = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, double const *, double const *, double const *, char const *, char const *const *)) GetProcAddress(h, "CPXLnewcols");
+            if (CPXXnewcols==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLnewcols' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXopenCPLEX = (CPXENVptr (*)(int *)) GetProcAddress(h, "CPXLopenCPLEX");
+            if (CPXXopenCPLEX==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLopenCPLEX' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXqpopt = (int (*)(CPXCENVptr, CPXLPptr)) GetProcAddress(h, "CPXLqpopt");
+            if (CPXXqpopt==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLqpopt' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetdblparam = (int (*)(CPXENVptr, int, double)) GetProcAddress(h, "CPXLsetdblparam");
+            if (CPXXsetdblparam==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLsetdblparam' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetdefaults = (int (*)(CPXENVptr)) GetProcAddress(h, "CPXLsetdefaults");
+            if (CPXXsetdefaults==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLsetdefaults' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetintparam = (int (*)(CPXENVptr, int, CPXINT)) GetProcAddress(h, "CPXLsetintparam");
+            if (CPXXsetintparam==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLsetintparam' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetlongparam = (int (*)(CPXENVptr, int, CPXLONG)) GetProcAddress(h, "CPXLsetlongparam");
+            if (CPXXsetlongparam==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLsetlongparam' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetstrparam = (int (*)(CPXENVptr, int, char const *)) GetProcAddress(h, "CPXLsetstrparam");
+            if (CPXXsetstrparam==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLsetstrparam' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsolution = (int (*)(CPXCENVptr, CPXCLPptr, int *, double *, double *, double *, double *, double *)) GetProcAddress(h, "CPXLsolution");
+            if (CPXXsolution==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLsolution' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXwriteprob = (int (*)(CPXCENVptr, CPXCLPptr, char const *, char const *)) GetProcAddress(h, "CPXLwriteprob");
+            if (CPXXwriteprob==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLwriteprob' in libcplex%s.%s", suffix, library_suffix); return 2; };
 #endif
 #if CPX_APIMODEL == CPX_APIMODEL_SMALL
             CPXXaddmipstarts = (int (*)(CPXCENVptr, CPXLPptr, int, CPXNNZ, CPXNNZ const *, CPXDIM const *, double const *, int const *, char const *const *)) GetProcAddress(h, "CPXSaddmipstarts");
+            if (CPXXaddmipstarts==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSaddmipstarts' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXaddqconstr = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, CPXNNZ, double, int, CPXDIM const *, double const *, CPXDIM const *, CPXDIM const *, double const *, char const *)) GetProcAddress(h, "CPXSaddqconstr");
+            if (CPXXaddqconstr==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSaddqconstr' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXaddrows = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, CPXDIM, CPXNNZ, double const *, char const *, CPXNNZ const *, CPXDIM const *, double const *, char const *const *, char const *const *)) GetProcAddress(h, "CPXSaddrows");
+            if (CPXXaddrows==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSaddrows' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXaddsos = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, CPXNNZ, char const *, CPXNNZ const *, CPXDIM const *, double const *, char const *const *)) GetProcAddress(h, "CPXSaddsos");
+            if (CPXXaddsos==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSaddsos' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcloseCPLEX = (int (*)(CPXENVptr *)) GetProcAddress(h, "CPXScloseCPLEX");
+            if (CPXXcloseCPLEX==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXScloseCPLEX' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcopyctype = (int (*)(CPXCENVptr, CPXLPptr, char const *)) GetProcAddress(h, "CPXScopyctype");
+            if (CPXXcopyctype==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXScopyctype' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcopylp = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, CPXDIM, int, double const *, double const *, char const *, CPXNNZ const *, CPXDIM const *, CPXDIM const *, double const *, double const *, double const *, double const *)) GetProcAddress(h, "CPXScopylp");
+            if (CPXXcopylp==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXScopylp' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcopyquad = (int (*)(CPXCENVptr, CPXLPptr, CPXNNZ const *, CPXDIM const *, CPXDIM const *, double const *)) GetProcAddress(h, "CPXScopyquad");
+            if (CPXXcopyquad==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXScopyquad' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcopystart = (int (*)(CPXCENVptr, CPXLPptr, int const *, int const *, double const *, double const *, double const *, double const *)) GetProcAddress(h, "CPXScopystart");
+            if (CPXXcopystart==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXScopystart' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcreateprob = (CPXLPptr (*)(CPXCENVptr, int *, char const *)) GetProcAddress(h, "CPXScreateprob");
+            if (CPXXcreateprob==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXScreateprob' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXfreeprob = (int (*)(CPXCENVptr, CPXLPptr *)) GetProcAddress(h, "CPXSfreeprob");
+            if (CPXXfreeprob==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSfreeprob' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetbase = (int (*)(CPXCENVptr, CPXCLPptr, int *, int *)) GetProcAddress(h, "CPXSgetbase");
+            if (CPXXgetbase==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetbase' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgeterrorstring = (CPXCCHARptr (*)(CPXCENVptr, int, char *)) GetProcAddress(h, "CPXSgeterrorstring");
+            if (CPXXgeterrorstring==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgeterrorstring' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetnumcols = (CPXDIM (*)(CPXCENVptr, CPXCLPptr)) GetProcAddress(h, "CPXSgetnumcols");
+            if (CPXXgetnumcols==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetnumcols' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetnumrows = (CPXDIM (*)(CPXCENVptr, CPXCLPptr)) GetProcAddress(h, "CPXSgetnumrows");
+            if (CPXXgetnumrows==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetnumrows' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetobjval = (int (*)(CPXCENVptr, CPXCLPptr, double *)) GetProcAddress(h, "CPXSgetobjval");
+            if (CPXXgetobjval==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetobjval' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetparamnum = (int (*)(CPXCENVptr, char const *, int *)) GetProcAddress(h, "CPXSgetparamnum");
+            if (CPXXgetparamnum==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetparamnum' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetparamtype = (int (*)(CPXCENVptr, int, int *)) GetProcAddress(h, "CPXSgetparamtype");
+            if (CPXXgetparamtype==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetparamtype' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetprobtype = (int (*)(CPXCENVptr, CPXCLPptr)) GetProcAddress(h, "CPXSgetprobtype");
+            if (CPXXgetprobtype==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetprobtype' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetslack = (int (*)(CPXCENVptr, CPXCLPptr, double *, CPXDIM, CPXDIM)) GetProcAddress(h, "CPXSgetslack");
+            if (CPXXgetslack==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetslack' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetstat = (int (*)(CPXCENVptr, CPXCLPptr)) GetProcAddress(h, "CPXSgetstat");
+            if (CPXXgetstat==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetstat' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetstatstring = (CPXCHARptr (*)(CPXCENVptr, int, char *)) GetProcAddress(h, "CPXSgetstatstring");
+            if (CPXXgetstatstring==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetstatstring' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetx = (int (*)(CPXCENVptr, CPXCLPptr, double *, CPXDIM, CPXDIM)) GetProcAddress(h, "CPXSgetx");
+            if (CPXXgetx==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetx' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXmipopt = (int (*)(CPXCENVptr, CPXLPptr)) GetProcAddress(h, "CPXSmipopt");
+            if (CPXXmipopt==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSmipopt' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXnewcols = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, double const *, double const *, double const *, char const *, char const *const *)) GetProcAddress(h, "CPXSnewcols");
+            if (CPXXnewcols==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSnewcols' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXopenCPLEX = (CPXENVptr (*)(int *)) GetProcAddress(h, "CPXSopenCPLEX");
+            if (CPXXopenCPLEX==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSopenCPLEX' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXqpopt = (int (*)(CPXCENVptr, CPXLPptr)) GetProcAddress(h, "CPXSqpopt");
+            if (CPXXqpopt==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSqpopt' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetdblparam = (int (*)(CPXENVptr, int, double)) GetProcAddress(h, "CPXSsetdblparam");
+            if (CPXXsetdblparam==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSsetdblparam' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetdefaults = (int (*)(CPXENVptr)) GetProcAddress(h, "CPXSsetdefaults");
+            if (CPXXsetdefaults==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSsetdefaults' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetintparam = (int (*)(CPXENVptr, int, CPXINT)) GetProcAddress(h, "CPXSsetintparam");
+            if (CPXXsetintparam==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSsetintparam' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetlongparam = (int (*)(CPXENVptr, int, CPXLONG)) GetProcAddress(h, "CPXSsetlongparam");
+            if (CPXXsetlongparam==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSsetlongparam' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetstrparam = (int (*)(CPXENVptr, int, char const *)) GetProcAddress(h, "CPXSsetstrparam");
+            if (CPXXsetstrparam==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSsetstrparam' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsolution = (int (*)(CPXCENVptr, CPXCLPptr, int *, double *, double *, double *, double *, double *)) GetProcAddress(h, "CPXSsolution");
+            if (CPXXsolution==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSsolution' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXwriteprob = (int (*)(CPXCENVptr, CPXCLPptr, char const *, char const *)) GetProcAddress(h, "CPXSwriteprob");
+            if (CPXXwriteprob==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSwriteprob' in libcplex%s.%s", suffix, library_suffix); return 2; };
 #endif
 
       #else // _WIN32
   #if CPX_APIMODEL == CPX_APIMODEL_LARGE
             CPXXaddmipstarts = (int (*)(CPXCENVptr, CPXLPptr, int, CPXNNZ, CPXNNZ const *, CPXDIM const *, double const *, int const *, char const *const *)) dlsym(h, "CPXLaddmipstarts");
+            if (CPXXaddmipstarts==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLaddmipstarts' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXaddqconstr = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, CPXNNZ, double, int, CPXDIM const *, double const *, CPXDIM const *, CPXDIM const *, double const *, char const *)) dlsym(h, "CPXLaddqconstr");
+            if (CPXXaddqconstr==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLaddqconstr' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXaddrows = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, CPXDIM, CPXNNZ, double const *, char const *, CPXNNZ const *, CPXDIM const *, double const *, char const *const *, char const *const *)) dlsym(h, "CPXLaddrows");
+            if (CPXXaddrows==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLaddrows' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXaddsos = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, CPXNNZ, char const *, CPXNNZ const *, CPXDIM const *, double const *, char const *const *)) dlsym(h, "CPXLaddsos");
+            if (CPXXaddsos==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLaddsos' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcloseCPLEX = (int (*)(CPXENVptr *)) dlsym(h, "CPXLcloseCPLEX");
+            if (CPXXcloseCPLEX==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLcloseCPLEX' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcopyctype = (int (*)(CPXCENVptr, CPXLPptr, char const *)) dlsym(h, "CPXLcopyctype");
+            if (CPXXcopyctype==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLcopyctype' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcopylp = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, CPXDIM, int, double const *, double const *, char const *, CPXNNZ const *, CPXDIM const *, CPXDIM const *, double const *, double const *, double const *, double const *)) dlsym(h, "CPXLcopylp");
+            if (CPXXcopylp==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLcopylp' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcopyquad = (int (*)(CPXCENVptr, CPXLPptr, CPXNNZ const *, CPXDIM const *, CPXDIM const *, double const *)) dlsym(h, "CPXLcopyquad");
+            if (CPXXcopyquad==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLcopyquad' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcopystart = (int (*)(CPXCENVptr, CPXLPptr, int const *, int const *, double const *, double const *, double const *, double const *)) dlsym(h, "CPXLcopystart");
+            if (CPXXcopystart==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLcopystart' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcreateprob = (CPXLPptr (*)(CPXCENVptr, int *, char const *)) dlsym(h, "CPXLcreateprob");
+            if (CPXXcreateprob==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLcreateprob' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXfreeprob = (int (*)(CPXCENVptr, CPXLPptr *)) dlsym(h, "CPXLfreeprob");
+            if (CPXXfreeprob==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLfreeprob' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetbase = (int (*)(CPXCENVptr, CPXCLPptr, int *, int *)) dlsym(h, "CPXLgetbase");
+            if (CPXXgetbase==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetbase' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgeterrorstring = (CPXCCHARptr (*)(CPXCENVptr, int, char *)) dlsym(h, "CPXLgeterrorstring");
+            if (CPXXgeterrorstring==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgeterrorstring' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetnumcols = (CPXDIM (*)(CPXCENVptr, CPXCLPptr)) dlsym(h, "CPXLgetnumcols");
+            if (CPXXgetnumcols==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetnumcols' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetnumrows = (CPXDIM (*)(CPXCENVptr, CPXCLPptr)) dlsym(h, "CPXLgetnumrows");
+            if (CPXXgetnumrows==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetnumrows' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetobjval = (int (*)(CPXCENVptr, CPXCLPptr, double *)) dlsym(h, "CPXLgetobjval");
+            if (CPXXgetobjval==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetobjval' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetparamnum = (int (*)(CPXCENVptr, char const *, int *)) dlsym(h, "CPXLgetparamnum");
+            if (CPXXgetparamnum==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetparamnum' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetparamtype = (int (*)(CPXCENVptr, int, int *)) dlsym(h, "CPXLgetparamtype");
+            if (CPXXgetparamtype==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetparamtype' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetprobtype = (int (*)(CPXCENVptr, CPXCLPptr)) dlsym(h, "CPXLgetprobtype");
+            if (CPXXgetprobtype==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetprobtype' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetslack = (int (*)(CPXCENVptr, CPXCLPptr, double *, CPXDIM, CPXDIM)) dlsym(h, "CPXLgetslack");
+            if (CPXXgetslack==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetslack' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetstat = (int (*)(CPXCENVptr, CPXCLPptr)) dlsym(h, "CPXLgetstat");
+            if (CPXXgetstat==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetstat' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetstatstring = (CPXCHARptr (*)(CPXCENVptr, int, char *)) dlsym(h, "CPXLgetstatstring");
+            if (CPXXgetstatstring==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetstatstring' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetx = (int (*)(CPXCENVptr, CPXCLPptr, double *, CPXDIM, CPXDIM)) dlsym(h, "CPXLgetx");
+            if (CPXXgetx==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLgetx' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXmipopt = (int (*)(CPXCENVptr, CPXLPptr)) dlsym(h, "CPXLmipopt");
+            if (CPXXmipopt==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLmipopt' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXnewcols = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, double const *, double const *, double const *, char const *, char const *const *)) dlsym(h, "CPXLnewcols");
+            if (CPXXnewcols==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLnewcols' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXopenCPLEX = (CPXENVptr (*)(int *)) dlsym(h, "CPXLopenCPLEX");
+            if (CPXXopenCPLEX==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLopenCPLEX' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXqpopt = (int (*)(CPXCENVptr, CPXLPptr)) dlsym(h, "CPXLqpopt");
+            if (CPXXqpopt==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLqpopt' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetdblparam = (int (*)(CPXENVptr, int, double)) dlsym(h, "CPXLsetdblparam");
+            if (CPXXsetdblparam==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLsetdblparam' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetdefaults = (int (*)(CPXENVptr)) dlsym(h, "CPXLsetdefaults");
+            if (CPXXsetdefaults==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLsetdefaults' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetintparam = (int (*)(CPXENVptr, int, CPXINT)) dlsym(h, "CPXLsetintparam");
+            if (CPXXsetintparam==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLsetintparam' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetlongparam = (int (*)(CPXENVptr, int, CPXLONG)) dlsym(h, "CPXLsetlongparam");
+            if (CPXXsetlongparam==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLsetlongparam' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetstrparam = (int (*)(CPXENVptr, int, char const *)) dlsym(h, "CPXLsetstrparam");
+            if (CPXXsetstrparam==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLsetstrparam' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsolution = (int (*)(CPXCENVptr, CPXCLPptr, int *, double *, double *, double *, double *, double *)) dlsym(h, "CPXLsolution");
+            if (CPXXsolution==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLsolution' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXwriteprob = (int (*)(CPXCENVptr, CPXCLPptr, char const *, char const *)) dlsym(h, "CPXLwriteprob");
+            if (CPXXwriteprob==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXLwriteprob' in libcplex%s.%s", suffix, library_suffix); return 2; };
 #endif
 #if CPX_APIMODEL == CPX_APIMODEL_SMALL
             CPXXaddmipstarts = (int (*)(CPXCENVptr, CPXLPptr, int, CPXNNZ, CPXNNZ const *, CPXDIM const *, double const *, int const *, char const *const *)) dlsym(h, "CPXSaddmipstarts");
+            if (CPXXaddmipstarts==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSaddmipstarts' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXaddqconstr = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, CPXNNZ, double, int, CPXDIM const *, double const *, CPXDIM const *, CPXDIM const *, double const *, char const *)) dlsym(h, "CPXSaddqconstr");
+            if (CPXXaddqconstr==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSaddqconstr' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXaddrows = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, CPXDIM, CPXNNZ, double const *, char const *, CPXNNZ const *, CPXDIM const *, double const *, char const *const *, char const *const *)) dlsym(h, "CPXSaddrows");
+            if (CPXXaddrows==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSaddrows' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXaddsos = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, CPXNNZ, char const *, CPXNNZ const *, CPXDIM const *, double const *, char const *const *)) dlsym(h, "CPXSaddsos");
+            if (CPXXaddsos==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSaddsos' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcloseCPLEX = (int (*)(CPXENVptr *)) dlsym(h, "CPXScloseCPLEX");
+            if (CPXXcloseCPLEX==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXScloseCPLEX' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcopyctype = (int (*)(CPXCENVptr, CPXLPptr, char const *)) dlsym(h, "CPXScopyctype");
+            if (CPXXcopyctype==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXScopyctype' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcopylp = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, CPXDIM, int, double const *, double const *, char const *, CPXNNZ const *, CPXDIM const *, CPXDIM const *, double const *, double const *, double const *, double const *)) dlsym(h, "CPXScopylp");
+            if (CPXXcopylp==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXScopylp' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcopyquad = (int (*)(CPXCENVptr, CPXLPptr, CPXNNZ const *, CPXDIM const *, CPXDIM const *, double const *)) dlsym(h, "CPXScopyquad");
+            if (CPXXcopyquad==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXScopyquad' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcopystart = (int (*)(CPXCENVptr, CPXLPptr, int const *, int const *, double const *, double const *, double const *, double const *)) dlsym(h, "CPXScopystart");
+            if (CPXXcopystart==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXScopystart' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXcreateprob = (CPXLPptr (*)(CPXCENVptr, int *, char const *)) dlsym(h, "CPXScreateprob");
+            if (CPXXcreateprob==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXScreateprob' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXfreeprob = (int (*)(CPXCENVptr, CPXLPptr *)) dlsym(h, "CPXSfreeprob");
+            if (CPXXfreeprob==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSfreeprob' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetbase = (int (*)(CPXCENVptr, CPXCLPptr, int *, int *)) dlsym(h, "CPXSgetbase");
+            if (CPXXgetbase==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetbase' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgeterrorstring = (CPXCCHARptr (*)(CPXCENVptr, int, char *)) dlsym(h, "CPXSgeterrorstring");
+            if (CPXXgeterrorstring==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgeterrorstring' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetnumcols = (CPXDIM (*)(CPXCENVptr, CPXCLPptr)) dlsym(h, "CPXSgetnumcols");
+            if (CPXXgetnumcols==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetnumcols' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetnumrows = (CPXDIM (*)(CPXCENVptr, CPXCLPptr)) dlsym(h, "CPXSgetnumrows");
+            if (CPXXgetnumrows==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetnumrows' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetobjval = (int (*)(CPXCENVptr, CPXCLPptr, double *)) dlsym(h, "CPXSgetobjval");
+            if (CPXXgetobjval==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetobjval' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetparamnum = (int (*)(CPXCENVptr, char const *, int *)) dlsym(h, "CPXSgetparamnum");
+            if (CPXXgetparamnum==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetparamnum' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetparamtype = (int (*)(CPXCENVptr, int, int *)) dlsym(h, "CPXSgetparamtype");
+            if (CPXXgetparamtype==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetparamtype' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetprobtype = (int (*)(CPXCENVptr, CPXCLPptr)) dlsym(h, "CPXSgetprobtype");
+            if (CPXXgetprobtype==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetprobtype' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetslack = (int (*)(CPXCENVptr, CPXCLPptr, double *, CPXDIM, CPXDIM)) dlsym(h, "CPXSgetslack");
+            if (CPXXgetslack==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetslack' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetstat = (int (*)(CPXCENVptr, CPXCLPptr)) dlsym(h, "CPXSgetstat");
+            if (CPXXgetstat==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetstat' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetstatstring = (CPXCHARptr (*)(CPXCENVptr, int, char *)) dlsym(h, "CPXSgetstatstring");
+            if (CPXXgetstatstring==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetstatstring' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXgetx = (int (*)(CPXCENVptr, CPXCLPptr, double *, CPXDIM, CPXDIM)) dlsym(h, "CPXSgetx");
+            if (CPXXgetx==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSgetx' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXmipopt = (int (*)(CPXCENVptr, CPXLPptr)) dlsym(h, "CPXSmipopt");
+            if (CPXXmipopt==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSmipopt' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXnewcols = (int (*)(CPXCENVptr, CPXLPptr, CPXDIM, double const *, double const *, double const *, char const *, char const *const *)) dlsym(h, "CPXSnewcols");
+            if (CPXXnewcols==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSnewcols' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXopenCPLEX = (CPXENVptr (*)(int *)) dlsym(h, "CPXSopenCPLEX");
+            if (CPXXopenCPLEX==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSopenCPLEX' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXqpopt = (int (*)(CPXCENVptr, CPXLPptr)) dlsym(h, "CPXSqpopt");
+            if (CPXXqpopt==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSqpopt' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetdblparam = (int (*)(CPXENVptr, int, double)) dlsym(h, "CPXSsetdblparam");
+            if (CPXXsetdblparam==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSsetdblparam' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetdefaults = (int (*)(CPXENVptr)) dlsym(h, "CPXSsetdefaults");
+            if (CPXXsetdefaults==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSsetdefaults' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetintparam = (int (*)(CPXENVptr, int, CPXINT)) dlsym(h, "CPXSsetintparam");
+            if (CPXXsetintparam==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSsetintparam' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetlongparam = (int (*)(CPXENVptr, int, CPXLONG)) dlsym(h, "CPXSsetlongparam");
+            if (CPXXsetlongparam==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSsetlongparam' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsetstrparam = (int (*)(CPXENVptr, int, char const *)) dlsym(h, "CPXSsetstrparam");
+            if (CPXXsetstrparam==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSsetstrparam' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXsolution = (int (*)(CPXCENVptr, CPXCLPptr, int *, double *, double *, double *, double *, double *)) dlsym(h, "CPXSsolution");
+            if (CPXXsolution==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSsolution' in libcplex%s.%s", suffix, library_suffix); return 2; };
             CPXXwriteprob = (int (*)(CPXCENVptr, CPXCLPptr, char const *, char const *)) dlsym(h, "CPXSwriteprob");
+            if (CPXXwriteprob==NULL) { snprintf(err_msg, err_msg_len, "Could not find symbol 'CPXSwriteprob' in libcplex%s.%s", suffix, library_suffix); return 2; };
 #endif
 
       #endif // _WIN32