diff --git a/dlib/dnn/cublas_dlibapi.cpp b/dlib/dnn/cublas_dlibapi.cpp
index 9273280c9..3a2d79d2b 100644
--- a/dlib/dnn/cublas_dlibapi.cpp
+++ b/dlib/dnn/cublas_dlibapi.cpp
@@ -25,7 +25,7 @@ static const char* cublas_get_error_string(cublasStatus_t s)
 
 // Check the return value of a call to the cuBLAS runtime for an error condition.
 #define CHECK_CUBLAS(call)                                                      \
-{                                                                              \
+do{                                                                              \
     const cublasStatus_t error = call;                                         \
     if (error != CUBLAS_STATUS_SUCCESS)                                        \
     {                                                                          \
@@ -34,7 +34,7 @@ static const char* cublas_get_error_string(cublasStatus_t s)
         sout << "code: " << error << ", reason: " << cublas_get_error_string(error);\
         throw dlib::cublas_error(sout.str());                            \
     }                                                                          \
-}
+}while(false)
 
 namespace dlib
 {
diff --git a/dlib/dnn/cudnn_dlibapi.cpp b/dlib/dnn/cudnn_dlibapi.cpp
index bff63478c..fe61ca715 100644
--- a/dlib/dnn/cudnn_dlibapi.cpp
+++ b/dlib/dnn/cudnn_dlibapi.cpp
@@ -36,7 +36,7 @@ static const char* cudnn_get_error_string(cudnnStatus_t s)
 
 // Check the return value of a call to the cuDNN runtime for an error condition.
 #define CHECK_CUDNN(call)                                                      \
-{                                                                              \
+do{                                                                              \
     const cudnnStatus_t error = call;                                         \
     if (error != CUDNN_STATUS_SUCCESS)                                        \
     {                                                                          \
@@ -45,7 +45,7 @@ static const char* cudnn_get_error_string(cudnnStatus_t s)
         sout << "code: " << error << ", reason: " << cudnn_get_error_string(error);\
         throw dlib::cudnn_error(sout.str());                            \
     }                                                                          \
-}
+}while(false)
 
 
 namespace dlib
diff --git a/dlib/dnn/curand_dlibapi.cpp b/dlib/dnn/curand_dlibapi.cpp
index 170988cce..698bfd0e8 100644
--- a/dlib/dnn/curand_dlibapi.cpp
+++ b/dlib/dnn/curand_dlibapi.cpp
@@ -24,7 +24,7 @@ static const char* curand_get_error_string(curandStatus_t s)
 
 // Check the return value of a call to the cuDNN runtime for an error condition.
 #define CHECK_CURAND(call)                                                      \
-{                                                                              \
+do{                                                                              \
     const curandStatus_t error = call;                                         \
     if (error != CURAND_STATUS_SUCCESS)                                        \
     {                                                                          \
@@ -33,7 +33,7 @@ static const char* curand_get_error_string(curandStatus_t s)
         sout << "code: " << error << ", reason: " << curand_get_error_string(error);\
         throw dlib::curand_error(sout.str());                            \
     }                                                                          \
-}
+}while(false)
 
 namespace dlib
 {