Add: julia-0.6.2

Former-commit-id: ccc667cf67d569f3fb3df39aa57c2134755a7551

julia-0.6.2/share/doc/julia/examples/embedding/embedding.c

@@ -0,0 +1,153 @@
+// This file is a part of Julia. License is MIT: https://julialang.org/license
+
+#include <julia.h>
+#include <stdio.h>
+#include <math.h>
+
+#ifdef _OS_WINDOWS_
+__declspec(dllexport) __cdecl
+#endif
+double my_c_sqrt(double x)
+{
+    return sqrt(x);
+}
+
+jl_value_t *checked_eval_string(const char* code)
+{
+    jl_value_t *result = jl_eval_string(code);
+    if (jl_exception_occurred()) {
+        // none of these allocate, so a gc-root (JL_GC_PUSH) is not necessary
+        jl_call2(jl_get_function(jl_base_module, "showerror"),
+                 jl_stderr_obj(),
+                 jl_exception_occurred());
+        jl_printf(jl_stderr_stream(), "\n");
+        jl_atexit_hook(1);
+        exit(1);
+    }
+    assert(result && "Missing return value but no exception occurred!");
+    return result;
+}
+
+int main()
+{
+    jl_init();
+
+    {
+        // Simple running of Julia code
+
+        checked_eval_string("println(sqrt(2.0))");
+    }
+
+    {
+        // Accessing the return value
+
+        jl_value_t *ret = checked_eval_string("sqrt(2.0)");
+        double retDouble = jl_unbox_float64(ret);
+        printf("sqrt(2.0) in C: %e\n", retDouble);
+        fflush(stdout);
+    }
+
+    {
+        // Same as above but with function handle (more flexible)
+
+        jl_function_t *func = jl_get_function(jl_base_module, "sqrt");
+        jl_value_t* argument = jl_box_float64(2.0);
+        jl_value_t* ret = jl_call1(func, argument);
+        double retDouble = jl_unbox_float64(ret);
+        printf("sqrt(2.0) in C: %e\n", retDouble);
+        fflush(stdout);
+    }
+
+    {
+        // 1D arrays
+
+        jl_value_t* array_type = jl_apply_array_type((jl_value_t*)jl_float64_type, 1);
+        jl_array_t* x          = jl_alloc_array_1d(array_type, 10);
+        // JL_GC_PUSH* is required here to ensure that `x` is not deleted before
+        // (aka, is gc-rooted until) the program reaches the corresponding JL_GC_POP()
+        JL_GC_PUSH1(&x);
+
+        double* xData = jl_array_data(x);
+
+        size_t i;
+        for (i = 0; i < jl_array_len(x); i++)
+            xData[i] = i;
+
+        jl_function_t *func  = jl_get_function(jl_base_module, "reverse!");
+        jl_call1(func, (jl_value_t*) x);
+
+        printf("x = [");
+        for (i = 0; i < jl_array_len(x); i++)
+            printf("%e ", xData[i]);
+        printf("]\n");
+        fflush(stdout);
+
+        JL_GC_POP();
+    }
+
+    {
+        // Defining a Julia function and calling it
+
+        checked_eval_string("my_func(x) = 2 * x");
+
+        jl_function_t *func = jl_get_function(jl_current_module, "my_func");
+        jl_value_t* arg = jl_box_float64(5.0);
+        double ret = jl_unbox_float64(jl_call1(func, arg));
+
+        printf("my_func(5.0) = %f\n", ret);
+        fflush(stdout);
+    }
+
+    {
+        // Calling a C function from Julia (from C)
+
+        // in a shared library (exported, by name)
+        checked_eval_string("println( ccall(:my_c_sqrt, Float64, (Float64,), 2.0) )");
+
+        // or via a pointer
+        jl_value_t *call_by_ptr = checked_eval_string(
+                "my_c_sqrt -> println( ccall(my_c_sqrt, Float64, (Float64,), 2.0) )");
+        jl_call1(call_by_ptr, jl_box_voidpointer(my_c_sqrt));
+    }
+
+    {
+        // Handling exceptions gracefully
+
+        jl_value_t *f = checked_eval_string("function this_function_has_no_methods end");
+        jl_call0(f);
+
+        if (jl_exception_occurred()) {
+            jl_call2(jl_get_function(jl_base_module, "showerror"),
+                     jl_stderr_obj(),
+                     jl_exception_occurred());
+            jl_printf(jl_stderr_stream(), "\n");
+        }
+
+    }
+
+    {
+        // Creating and using a native C function handle
+        // to a Julia function signature
+
+        checked_eval_string(
+                "function bar()\n"
+                "    println(\"called bar\")\n"
+                "    random_return_value = 42\n"
+                "end");
+        checked_eval_string(
+                "function bar_from_c()\n"
+                "    bar()\n"
+                "    nothing\n"
+                "end");
+        typedef void (*Func_VOID__VOID)(void);
+        jl_value_t *pbar = jl_eval_string("cfunction(bar_from_c, Void, ())");
+        Func_VOID__VOID bar = (Func_VOID__VOID)jl_unbox_voidpointer(pbar);
+        bar();
+        checked_eval_string("bar() = println(\"calling new bar\")");
+        bar();
+    }
+
+    int ret = 0;
+    jl_atexit_hook(ret);
+    return ret;
+}