Can't Compile GZDoom

Hi all,

Trying to build GZDoom on Linux (Fedora 20 -- I know it's outdated... Don't judge me), and I get the following error:

[ 58%] Building CXX object src/CMakeFiles/zdoom.dir/gl/shaders/gl_ambientshader.cpp.o
/ptmp/gzdoom_build/gzdoom/src/gl/shaders/gl_ambientshader.cpp: In member function ‘void FLinearDepthShader::Bind()’:
/ptmp/gzdoom_build/gzdoom/src/gl/shaders/gl_ambientshader.cpp:42:13: error: ‘make_unique’ is not a member of ‘std’
   mShader = std::make_unique<FShaderProgram>();
             ^
/ptmp/gzdoom_build/gzdoom/src/gl/shaders/gl_ambientshader.cpp:42:44: error: expected primary-expression before ‘>’ token
   mShader = std::make_unique<FShaderProgram>();
                                            ^
/ptmp/gzdoom_build/gzdoom/src/gl/shaders/gl_ambientshader.cpp:42:46: error: expected primary-expression before ‘)’ token
   mShader = std::make_unique<FShaderProgram>();
                                              ^
/ptmp/gzdoom_build/gzdoom/src/gl/shaders/gl_ambientshader.cpp: In member function ‘void FSSAOShader::Bind()’:
/ptmp/gzdoom_build/gzdoom/src/gl/shaders/gl_ambientshader.cpp:70:13: error: ‘make_unique’ is not a member of ‘std’
   mShader = std::make_unique<FShaderProgram>();
             ^
/ptmp/gzdoom_build/gzdoom/src/gl/shaders/gl_ambientshader.cpp:70:44: error: expected primary-expression before ‘>’ token
   mShader = std::make_unique<FShaderProgram>();
                                            ^
/ptmp/gzdoom_build/gzdoom/src/gl/shaders/gl_ambientshader.cpp:70:46: error: expected primary-expression before ‘)’ token
   mShader = std::make_unique<FShaderProgram>();
                                              ^
/ptmp/gzdoom_build/gzdoom/src/gl/shaders/gl_ambientshader.cpp: In member function ‘void FSSAOCombineShader::Bind()’:
/ptmp/gzdoom_build/gzdoom/src/gl/shaders/gl_ambientshader.cpp:146:13: error: ‘make_unique’ is not a member of ‘std’
   mShader = std::make_unique<FShaderProgram>();
             ^
/ptmp/gzdoom_build/gzdoom/src/gl/shaders/gl_ambientshader.cpp:146:44: error: expected primary-expression before ‘>’ token
   mShader = std::make_unique<FShaderProgram>();
                                            ^
/ptmp/gzdoom_build/gzdoom/src/gl/shaders/gl_ambientshader.cpp:146:46: error: expected primary-expression before ‘)’ token
   mShader = std::make_unique<FShaderProgram>();
                                              ^
make[2]: *** [src/CMakeFiles/zdoom.dir/gl/shaders/gl_ambientshader.cpp.o] Error 1
make[1]: *** [src/CMakeFiles/zdoom.dir/all] Error 2
make: *** [all] Error 2

I'm guessing that the first error is the only one that matters... Is there a fix for this? I already checked that I have the minimum gcc/cmake versions required. Not sure what else to try.

Thanks!

This error means your compiler does not support the std::make_unique<T> template function, which is formally part of C++14 but generally available for most C++11 implementations as well.

You can fix it by replacing all those lines with mShader.reset(new FShaderProgram()) instead.

^ Worked like a charm... thank you kindly! :-)

11 minutes ago, dpJudas said:

This error means your compiler does not support the std::make_unique<T> template function, which is formally part of C++14 but generally available for most C++11 implementations as well.

 

Why did you use C++14 stuff if there's a working equivalent in C++11?

Because frankly I figured if it worked on MSVC, then it would work everywhere. I didn't factor in very old versions of GCC into that.

Encountered the same bug on release g2.4.0  on Ubuntu 14.04 LTS 64 bit. It's still long-term-supported, but old-ish.

Following the gzdoom wiki steps, it compiles by default with /usr/bin/c++ which appears to be a wrapper for gcc (Ubuntu 4.8.4-2ubuntu1~14.04.3) 4.8.4

The normal CMakeFlags include -std=gnu++1y . I tried to change the CXX_FLAGS to adding -std=c++14 , but that option is unrecognized until a later gcc (5.2 I remember reading). Then I tried adding -std=c++1y, which is recognized, but I guess still doesn't include the feature.

your patch did resolve that issue. Thanks.

--- gl_ambientshader.cpp.orig	2017-04-18 02:30:41.462766707 -0700
+++ gl_ambientshader.cpp	2017-04-18 02:34:44.638760737 -0700
@@ -39,7 +39,7 @@
 
 	if (!mShader)
 	{
-		mShader = std::make_unique<FShaderProgram>();
+		mShader.reset(new FShaderProgram());
 		mShader->Compile(FShaderProgram::Vertex, "shaders/glsl/screenquad.vp", "", 330);
 		mShader->Compile(FShaderProgram::Fragment, "shaders/glsl/lineardepth.fp", multisample ? "#define MULTISAMPLE\n" : "", 330);
 		mShader->SetFragDataLocation(0, "FragColor");
@@ -67,7 +67,7 @@
 
 	if (!mShader)
 	{
-		mShader = std::make_unique<FShaderProgram>();
+		mShader.reset(new FShaderProgram());
 		mShader->Compile(FShaderProgram::Vertex, "shaders/glsl/screenquad.vp", "", 330);
 		mShader->Compile(FShaderProgram::Fragment, "shaders/glsl/ssao.fp", GetDefines(gl_ssao, multisample), 330);
 		mShader->SetFragDataLocation(0, "FragColor");
@@ -143,7 +143,7 @@
 
 	if (!mShader)
 	{
-		mShader = std::make_unique<FShaderProgram>();
+		mShader.reset(new FShaderProgram());
 		mShader->Compile(FShaderProgram::Vertex, "shaders/glsl/screenquad.vp", "", 330);
 		mShader->Compile(FShaderProgram::Fragment, "shaders/glsl/ssaocombine.fp", multisample ? "#define MULTISAMPLE\n" : "", 330);
 		mShader->SetFragDataLocation(0, "FragColor");

Not knowing much about that code, it seems worrying to invoke methods on something which satisfies (!mShader). But I guess that's done before the check as well. Operator overloading for logical not?

mShader is a smart pointer. The operation you are concerned about is not with the object being pointed to, but with the pointer itself (i.e. it sets it.)