diff --git a/dlib/base64/base64_kernel_1.cpp b/dlib/base64/base64_kernel_1.cpp
index 06cae3d95..5b48c789e 100644
--- a/dlib/base64/base64_kernel_1.cpp
+++ b/dlib/base64/base64_kernel_1.cpp
@@ -190,20 +190,20 @@ namespace dlib
                     case CR:
                         ch = '\r';
                         if (out.sputn(&ch,1)!=1)
-                            throw std::ios_base::failure("error occured in the base64 object");
+                            throw std::ios_base::failure("error occurred in the base64 object");
                         break;
                     case LF:
                         ch = '\n';
                         if (out.sputn(&ch,1)!=1)
-                            throw std::ios_base::failure("error occured in the base64 object");
+                            throw std::ios_base::failure("error occurred in the base64 object");
                         break;
                     case CRLF:
                         ch = '\r';
                         if (out.sputn(&ch,1)!=1)
-                            throw std::ios_base::failure("error occured in the base64 object");
+                            throw std::ios_base::failure("error occurred in the base64 object");
                         ch = '\n';
                         if (out.sputn(&ch,1)!=1)
-                            throw std::ios_base::failure("error occured in the base64 object");
+                            throw std::ios_base::failure("error occurred in the base64 object");
                         break;
                     default:
                         DLIB_CASSERT(false,"this should never happen");
@@ -235,7 +235,7 @@ namespace dlib
                 // write the encoded bytes to the output stream
                 if (out.sputn(reinterpret_cast<char*>(&outbuf),4)!=4)
                 {
-                    throw std::ios_base::failure("error occured in the base64 object");
+                    throw std::ios_base::failure("error occurred in the base64 object");
                 }
 
                 // get 3 more input bytes
@@ -265,7 +265,7 @@ namespace dlib
                 // write the encoded bytes to the output stream
                 if (out.sputn(reinterpret_cast<char*>(&outbuf),4)!=4)
                 {
-                    throw std::ios_base::failure("error occured in the base64 object");
+                    throw std::ios_base::failure("error occurred in the base64 object");
                 }
 
 
@@ -292,7 +292,7 @@ namespace dlib
                 // write the encoded bytes to the output stream
                 if (out.sputn(reinterpret_cast<char*>(&outbuf),4)!=4)
                 {
-                    throw std::ios_base::failure("error occured in the base64 object");
+                    throw std::ios_base::failure("error occurred in the base64 object");
                 }
 
                 break;
@@ -370,7 +370,7 @@ namespace dlib
                 // write the encoded bytes to the output stream
                 if (out.sputn(reinterpret_cast<char*>(&outbuf),outsize)!=outsize)
                 {
-                    throw std::ios_base::failure("error occured in the base64 object");
+                    throw std::ios_base::failure("error occurred in the base64 object");
                 }
             }
 
diff --git a/dlib/bit_stream/bit_stream_kernel_1.cpp b/dlib/bit_stream/bit_stream_kernel_1.cpp
index ad3d63ef6..f49db14d5 100644
--- a/dlib/bit_stream/bit_stream_kernel_1.cpp
+++ b/dlib/bit_stream/bit_stream_kernel_1.cpp
@@ -121,7 +121,7 @@ namespace dlib
             buffer <<= 8 - buffer_size;
             if (osp->rdbuf()->sputn(reinterpret_cast<char*>(&buffer),1) == 0)
             {
-                throw std::ios_base::failure("error occured in the bit_stream object");
+                throw std::ios_base::failure("error occurred in the bit_stream object");
             }
 
             buffer_size = 0;
diff --git a/dlib/entropy_encoder/entropy_encoder_kernel_1.cpp b/dlib/entropy_encoder/entropy_encoder_kernel_1.cpp
index 028609d05..effcf3123 100644
--- a/dlib/entropy_encoder/entropy_encoder_kernel_1.cpp
+++ b/dlib/entropy_encoder/entropy_encoder_kernel_1.cpp
@@ -127,7 +127,7 @@ namespace dlib
                 {
                     if (streambuf->sputn(reinterpret_cast<char*>(&buf),1)==0)
                     {
-                        throw std::ios_base::failure("error occured in the entropy_encoder object");
+                        throw std::ios_base::failure("error occurred in the entropy_encoder object");
                     }
                     buf = 0;
                     buf_used = 0;
@@ -189,26 +189,26 @@ namespace dlib
         }
 
         if (streambuf->sputn(reinterpret_cast<char*>(&buf),1) == 0)
-            throw std::ios_base::failure("error occured in the entropy_encoder object");
+            throw std::ios_base::failure("error occurred in the entropy_encoder object");
 
 
 
         buf = static_cast<unsigned char>((low >> 24)&0xFF);
         if (streambuf->sputn(reinterpret_cast<char*>(&buf),1) == 0)
-            throw std::ios_base::failure("error occured in the entropy_encoder object");
+            throw std::ios_base::failure("error occurred in the entropy_encoder object");
 
 
 
 
         buf = static_cast<unsigned char>((low >> 16)&0xFF);
         if (streambuf->sputn(reinterpret_cast<char*>(&buf),1)==0)
-            throw std::ios_base::failure("error occured in the entropy_encoder object");
+            throw std::ios_base::failure("error occurred in the entropy_encoder object");
 
 
 
         buf = static_cast<unsigned char>((low >> 8)&0xFF);
         if (streambuf->sputn(reinterpret_cast<char*>(&buf),1)==0)
-            throw std::ios_base::failure("error occured in the entropy_encoder object");
+            throw std::ios_base::failure("error occurred in the entropy_encoder object");
 
 
 
@@ -216,7 +216,7 @@ namespace dlib
         {
             buf = static_cast<unsigned char>((low)&0xFF);
             if (streambuf->sputn(reinterpret_cast<char*>(&buf),1)==0)
-                throw std::ios_base::failure("error occured in the entropy_encoder object");
+                throw std::ios_base::failure("error occurred in the entropy_encoder object");
         }
     
 
diff --git a/dlib/entropy_encoder/entropy_encoder_kernel_2.cpp b/dlib/entropy_encoder/entropy_encoder_kernel_2.cpp
index d88030f2b..4f64a6155 100644
--- a/dlib/entropy_encoder/entropy_encoder_kernel_2.cpp
+++ b/dlib/entropy_encoder/entropy_encoder_kernel_2.cpp
@@ -170,7 +170,7 @@ namespace dlib
                 // write buf to the output stream
                 if (streambuf->sputn(reinterpret_cast<char*>(&buf),1)==0)
                 {
-                    throw std::ios_base::failure("error occured in the entropy_encoder object");
+                    throw std::ios_base::failure("error occurred in the entropy_encoder object");
                 }                   
                 
             } 
@@ -194,25 +194,25 @@ namespace dlib
 
         buf = static_cast<unsigned char>((low >> 24)&0xFF);
         if (streambuf->sputn(reinterpret_cast<char*>(&buf),1) == 0)
-            throw std::ios_base::failure("error occured in the entropy_encoder object");
+            throw std::ios_base::failure("error occurred in the entropy_encoder object");
 
 
 
 
         buf = static_cast<unsigned char>((low >> 16)&0xFF);
         if (streambuf->sputn(reinterpret_cast<char*>(&buf),1)==0)
-            throw std::ios_base::failure("error occured in the entropy_encoder object");
+            throw std::ios_base::failure("error occurred in the entropy_encoder object");
 
 
 
         buf = static_cast<unsigned char>((low >> 8)&0xFF);
         if (streambuf->sputn(reinterpret_cast<char*>(&buf),1)==0)
-            throw std::ios_base::failure("error occured in the entropy_encoder object");
+            throw std::ios_base::failure("error occurred in the entropy_encoder object");
 
 
         buf = static_cast<unsigned char>((low)&0xFF);
         if (streambuf->sputn(reinterpret_cast<char*>(&buf),1)==0)
-            throw std::ios_base::failure("error occured in the entropy_encoder object");
+            throw std::ios_base::failure("error occurred in the entropy_encoder object");