update c bindings

Author: alphaville

open-codegen/opengen/templates/c/example_optimizer_c_bindings.c

@@ -20,12 +20,30 @@
  */
 
 #include <stdio.h>
+#include <stdlib.h>
 #include "{{meta.optimizer_name}}_bindings.h"
 
 /*
  * Feel free to customize the following code...
  */
 
+static const char *exit_status_to_string({{meta.optimizer_name}}ExitStatus exit_status) {
+    switch (exit_status) {
+        case {{meta.optimizer_name}}Converged:
+            return "Converged";
+        case {{meta.optimizer_name}}NotConvergedIterations:
+            return "NotConvergedIterations";
+        case {{meta.optimizer_name}}NotConvergedOutOfTime:
+            return "NotConvergedOutOfTime";
+        case {{meta.optimizer_name}}NotConvergedCost:
+            return "NotConvergedCost";
+        case {{meta.optimizer_name}}NotConvergedNotFiniteComputation:
+            return "NotConvergedNotFiniteComputation";
+        default:
+            return "Unknown";
+    }
+}
+
 int main(void) {
     int i;
 
@@ -45,28 +63,18 @@ int main(void) {
 
     /* obtain cache           */
     {{meta.optimizer_name}}Cache *cache = {{meta.optimizer_name}}_new();
+    if (cache == NULL) {
+        fprintf(stderr, "Could not allocate solver cache\n");
+        return EXIT_FAILURE;
+    }
 
     /* solve                  */
     {{meta.optimizer_name}}SolverStatus status = {{meta.optimizer_name}}_solve(cache, u, p, {% if problem.dim_constraints_aug_lagrangian() > 0 %}y{% else %}0{% endif %}, &init_penalty);
 
-    /* print results */
-    printf("\n\n-------------------------------------------------\n");
-    printf("  Solution\n");
-    printf("-------------------------------------------------\n");
-
-    for (i = 0; i < {{meta.optimizer_name|upper}}_NUM_DECISION_VARIABLES; ++i) {
-        printf("u[%d] = %g\n", i, u[i]);
-    }
-
-    printf("\n");
-    for (i = 0; i < {{meta.optimizer_name|upper}}_N1; ++i) {
-        printf("y[%d] = %g\n", i, status.lagrange[i]);
-    }
-
     printf("\n\n-------------------------------------------------\n");
     printf("  Solver Statistics\n");
     printf("-------------------------------------------------\n");
-    printf("exit status      : %d\n", status.exit_status);
+    printf("exit status      : %d (%s)\n", status.exit_status, exit_status_to_string(status.exit_status));
     printf("error code       : %d\n", status.error_code);
     printf("error message    : %s\n", status.error_message);
     printf("iterations       : %lu\n", status.num_inner_iterations);
@@ -78,10 +86,34 @@ int main(void) {
     printf("Cost             : %f\n", status.cost);
     printf("||FRP||          : %f\n\n", status.last_problem_norm_fpr);
 
+    if (status.error_code != 0) {
+        fprintf(stderr, "Solver returned an error; solution vector is not printed.\n");
+        {{meta.optimizer_name}}_free(cache);
+        return EXIT_FAILURE;
+    }
+
+    if (status.exit_status != {{meta.optimizer_name}}Converged) {
+        fprintf(stderr, "Warning: solver did not converge, printing best available iterate.\n");
+    }
+
+    /* print results */
+    printf("\n\n-------------------------------------------------\n");
+    printf("  Solution\n");
+    printf("-------------------------------------------------\n");
+
+    for (i = 0; i < {{meta.optimizer_name|upper}}_NUM_DECISION_VARIABLES; ++i) {
+        printf("u[%d] = %g\n", i, u[i]);
+    }
+
+    printf("\n");
+    for (i = 0; i < {{meta.optimizer_name|upper}}_N1; ++i) {
+        printf("y[%d] = %g\n", i, status.lagrange[i]);
+    }
+
 
 
     /* free memory */
     {{meta.optimizer_name}}_free(cache);
 
-    return 0;
+    return EXIT_SUCCESS;
 }

open-codegen/opengen/templates/c/optimizer_cinterface.rs.jinja

@@ -1,5 +1,5 @@
 {% if activate_clib_generation -%}
-// ---Export functionality from Rust to C/C++------------------------------------------------------------
+// ---Export functionality from Rust to C/C++ --------------
 
 /// Solver cache (structure `{{meta.optimizer_name}}Cache`)
 ///