diff --git a/pyrasite/injector.py b/pyrasite/injector.py
index 067fad1..b1832da 100644
--- a/pyrasite/injector.py
+++ b/pyrasite/injector.py
@@ -23,18 +23,18 @@ def inject(pid, filename, verbose=False, gdb_prefix=''):
     """Executes a file in a running Python process."""
     filename = os.path.abspath(filename)
     gdb_cmds = [
-        'PyGILState_Ensure()',
-        'PyRun_SimpleString("'
+        '((int (*)())PyGILState_Ensure)()',
+        '((int (*)(const char *))PyRun_SimpleString)("'
             'import sys; sys.path.insert(0, \\"%s\\"); '
             'sys.path.insert(0, \\"%s\\"); '
             'exec(open(\\"%s\\").read())")' %
                 (os.path.dirname(filename),
                 os.path.abspath(os.path.join(os.path.dirname(__file__), '..')),
                 filename),
-        'PyGILState_Release($1)',
+        '((void (*) (int) )PyGILState_Release)($1)',
         ]
-    p = subprocess.Popen('%sgdb -p %d -batch %s' % (gdb_prefix, pid,
-        ' '.join(["-eval-command='call %s'" % cmd for cmd in gdb_cmds])),
+    cmd = '%sgdb -p %d -batch %s' % (gdb_prefix, pid, ' '.join(["-eval-command='call %s'" % cmd for cmd in gdb_cmds]))
+    p = subprocess.Popen(cmd,
         shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
     out, err = p.communicate()
     if verbose:
@@ -56,4 +56,4 @@ def inject_win(pid, filename, verbose=False, gdb_prefix=''):
             print(out)
             print(err)
 
-    inject = inject_win
\ No newline at end of file
+    inject = inject_win