X-Git-Url: http://wagner.pp.ru/gitweb/?a=blobdiff_plain;f=ctypescrypto%2Fexception.py;h=30c138e43aa5ba52651243267abe0cdf974244fa;hb=92df3e73921ba7b8756bfab1af4189dab7cc610e;hp=f0f3c5343238cabcd382c68ebe03e9738760c7fc;hpb=1ff9b1899959673512927b6afa317855908b7073;p=oss%2Fctypescrypto.git

diff --git a/ctypescrypto/exception.py b/ctypescrypto/exception.py
index f0f3c53..30c138e 100644
--- a/ctypescrypto/exception.py
+++ b/ctypescrypto/exception.py
@@ -1,6 +1,21 @@
+"""
+Exception which extracts libcrypto error information
+"""
 from ctypes import *
 from ctypescrypto import libcrypto
 strings_loaded=False
+
+__all__ = ['LibCryptoError','clear_err_stack']
+
+def _check_null(s):
+	"""
+	Handle transparently NULL returned from error reporting functions
+	instead of strings
+	"""
+	if s is None:	
+		return ""
+	return s
+
 class LibCryptoError(Exception):
 	"""
 		Exception for libcrypto errors. Adds all the info, which can be
@@ -15,9 +30,9 @@ class LibCryptoError(Exception):
 		e=libcrypto.ERR_get_error()
 		m = msg
 		while e != 0:
-			m+="\n\t"+libcrypto.ERR_lib_error_string(e)+":"+\
-			  libcrypto.ERR_func_error_string(e)+":"+\
-			  libcrypto.ERR_reason_error_string(e)
+			m+="\n\t"+_check_null(libcrypto.ERR_lib_error_string(e))+":"+\
+			  _check_null(libcrypto.ERR_func_error_string(e))+":"+\
+			  _check_null(libcrypto.ERR_reason_error_string(e))
 			e=libcrypto.ERR_get_error()
 		self.args=(m,)