Fixed delayed stderr output.

README.md

@@ -27,8 +27,8 @@ Works only on Linux and OS X. Windows is not supported yet. If you want to use t
 ```bash
 git clone https://github.com/XaverKlemenschits/jupyter-c-kernel.git
 cd jupyter-c-kernel
-pip install -e .
-cd jupyter_c_kernel && install_c_kernel --user
+pip install -e .  # for system install: sudo install .
+cd jupyter_c_kernel && install_c_kernel --user # for sys install: sudo install_c_kernel
 # now you can start the notebook
 jupyter notebook
 ```

jupyter_c_kernel/kernel.py

@@ -61,6 +61,10 @@ class RealTimeSubprocess(subprocess.Popen):
                 size -= 1
             return res
 
+        stderr_contents = read_all_from_queue(self._stderr_queue)
+        if stderr_contents:
+            self._write_to_stderr(stderr_contents.decode())
+
         stdout_contents = read_all_from_queue(self._stdout_queue)
         if stdout_contents:
             contents = stdout_contents.decode()
@@ -80,10 +84,6 @@ class RealTimeSubprocess(subprocess.Popen):
             else:
                 self._write_to_stdout(contents)
 
-        stderr_contents = read_all_from_queue(self._stderr_queue)
-        if stderr_contents:
-            self._write_to_stderr(stderr_contents.decode())
-
 
 class CKernel(Kernel):
     implementation = 'jupyter_c_kernel'
@@ -152,6 +152,7 @@ class CKernel(Kernel):
 
     def compile_with_gcc(self, source_filename, binary_filename, cflags=None, ldflags=None):
         # cflags = ['-std=c89', '-pedantic', '-fPIC', '-shared', '-rdynamic'] + cflags
+        # cflags = ['-std=c99', '-Wdeclaration-after-statement', '-Wvla', '-fPIC', '-shared', '-rdynamic'] + cflags
         # cflags = ['-std=iso9899:199409', '-pedantic', '-fPIC', '-shared', '-rdynamic'] + cflags
         # cflags = ['-std=c99', '-pedantic', '-fPIC', '-shared', '-rdynamic'] + cflags
         cflags = ['-std=c11', '-pedantic', '-fPIC', '-shared', '-rdynamic'] + cflags

jupyter_c_kernel/resources/stdio_wrap.h

@@ -60,7 +60,7 @@ char checkInputRequest() {
 /* Need to define vscanf for c89.
   TODO: This is a bit risky, since the underlying glibc does not
   have to include this if it is old. If it does not, linking will fail.
-  The only safe way is reimplementing the whole function. */
+  The better way would be readin via sscanf. */
 
 /* Read formatted input from stdin into argument list ARG.