Implement rb_syserr_new c function

It's already defined in cext.rb just not exposed in C.

Author: rwstauner

CHANGELOG.md

@@ -34,6 +34,7 @@ Compatibility:
 * Add `Module#undefined_instance_methods` (#3039, @itarato).
 * Add `Thread.each_caller_location` (#3039, @itarato).
 * Add `timeout` argument to `Thread::SizedQueue#push` (#3039, @itarato).
+* Add `rb_syserr_new` function (#3175, @rwstauner).
 
 Performance:
 

lib/cext/ABI_version.txt

@@ -1 +1 @@
-9
+10

spec/ruby/optional/capi/exception_spec.rb

@@ -100,6 +100,22 @@
     end
   end
 
+  describe "rb_syserr_new" do
+    it "returns system error with nil message" do
+      exception = @s.rb_syserr_new(Errno::ENOENT::Errno, nil)
+      exception.class.should == Errno::ENOENT
+      exception.message.should include("No such file or directory")
+      exception.should.is_a?(SystemCallError)
+    end
+
+    it "returns system error with custom message" do
+      exception = @s.rb_syserr_new(Errno::ENOENT::Errno, "custom message")
+      exception.message.should include("custom message")
+      exception.class.should == Errno::ENOENT
+      exception.should.is_a?(SystemCallError)
+    end
+  end
+
   describe "rb_syserr_new_str" do
     it "returns system error with nil message" do
       const = Errno::ENOENT

spec/ruby/optional/capi/ext/exception_spec.c

@@ -36,6 +36,15 @@ VALUE exception_spec_rb_set_errinfo(VALUE self, VALUE exc) {
   return Qnil;
 }
 
+VALUE exception_spec_rb_syserr_new(VALUE self, VALUE num, VALUE msg) {
+  char *cstr;
+  if(msg != Qnil) {
+    cstr = StringValuePtr(msg);
+  }
+  int n = NUM2INT(num);
+  return rb_syserr_new(n, cstr);
+}
+
 VALUE exception_spec_rb_syserr_new_str(VALUE self, VALUE num, VALUE msg) {
   int n = NUM2INT(num);
   return rb_syserr_new_str(n, msg);
@@ -55,6 +64,7 @@ void Init_exception_spec(void) {
   rb_define_method(cls, "rb_exc_new3", exception_spec_rb_exc_new3, 1);
   rb_define_method(cls, "rb_exc_raise", exception_spec_rb_exc_raise, 1);
   rb_define_method(cls, "rb_set_errinfo", exception_spec_rb_set_errinfo, 1);
+  rb_define_method(cls, "rb_syserr_new", exception_spec_rb_syserr_new, 2);
   rb_define_method(cls, "rb_syserr_new_str", exception_spec_rb_syserr_new_str, 2);
   rb_define_method(cls, "rb_make_exception", exception_spec_rb_make_exception, 1);
 }

src/main/c/cext/exception.c

@@ -72,6 +72,11 @@ void rb_sys_fail(const char *message) {
   rb_syserr_fail(n, message);
 }
 
+VALUE rb_syserr_new(int n, const char *mesg) {
+  VALUE arg = mesg ? rb_str_new_cstr(mesg) : Qnil;
+  return rb_syserr_new_str(n, arg);
+}
+
 VALUE rb_syserr_new_str(int n, VALUE mesg) {
   return RUBY_CEXT_INVOKE("rb_syserr_new", INT2FIX(n), mesg);
 }