如何执行此DirectFB示例？

Question

我从下面的directFB示例代码中得到了教程

#include <stdio.h>
#include <unistd.h>

#include <directfb/directfb.h>

static IDirectFB *dfb = NULL;
static IDirectFBSurface *primary = NULL;
static int screen_width = 0;
static int screen_height = 0;
#define DFBCHECK(x...)                                         \
  {                                                            \
    DFBResult err = x;                                         \
                                                               \
    if (err != DFB_OK)                                         \
      {                                                        \
        fprintf( stderr, "%s <%d>:\n\t", __FILE__, __LINE__ ); \
        DirectFBErrorFatal( #x, err );                         \
      }                                                        \
  }
int main(int argc, char **argv) {

    DFBSurfaceDescription dsc;
    DFBCHECK(DirectFBInit (&argc, &argv));
    DFBCHECK(DirectFBCreate (&dfb));
    DFBCHECK(dfb->SetCooperativeLevel (dfb, DFSCL_FULLSCREEN));
    dsc.flags = DSDESC_CAPS;
    dsc.caps = DSCAPS_PRIMARY | DSCAPS_FLIPPING;
    DFBCHECK(dfb->CreateSurface( dfb, &dsc, &primary ));
    DFBCHECK(primary->GetSize (primary, &screen_width, &screen_height));
    DFBCHECK(primary->FillRectangle (primary, 0, 0, screen_width, screen_height));
    DFBCHECK(primary->SetColor (primary, 0x80, 0x80, 0xff, 0xff));
    DFBCHECK(primary->DrawLine (primary, 0, screen_height / 2, screen_width - 1, screen_height / 2));
    DFBCHECK(primary->Flip (primary, NULL, 0));
    sleep(5);
    primary->Release(primary);
    dfb->Release(dfb);
    return 23;
}

我试图编译并得到错误(来自gnome终端)：

$ g++ Test01HorizontalLine.cpp -I /usr/local/include/directfb/
Test01HorizontalLine.cpp: In function ‘int main(int, char**)’:
Test01HorizontalLine.cpp:27: error: invalid conversion from ‘int’ to ‘DFBSurfaceCapabilities’
Test01HorizontalLine.cpp:33: error: invalid conversion from ‘int’ to ‘DFBSurfaceFlipFlags’

我正在使用DFB 1.4.11 (我不能更新我当前的项目)。我怎样才能让这个样本运行？(新手)

--更新

在更新行后(如@jclin所述)：

dsc.caps = DFBSurfaceCapabilities(DSCAPS_PRIMARY | DSCAPS_FLIPPING);  
...  
primary->Flip(primary, NULL, DFBSurfaceFlipFlags(0));  

结果是：

$ g++ Test01HorizontalLine.cpp -I /usr/local/include/directfb/
/tmp/cc6iUS1W.o: In function `main':
Test01HorizontalLine.cpp:(.text+0x1c): undefined reference to `DirectFBInit'
Test01HorizontalLine.cpp:(.text+0x61): undefined reference to `DirectFBErrorFatal'
Test01HorizontalLine.cpp:(.text+0x6d): undefined reference to `DirectFBCreate'
Test01HorizontalLine.cpp:(.text+0xb2): undefined reference to `DirectFBErrorFatal'
Test01HorizontalLine.cpp:(.text+0x111): undefined reference to `DirectFBErrorFatal'
Test01HorizontalLine.cpp:(.text+0x188): undefined reference to `DirectFBErrorFatal'
Test01HorizontalLine.cpp:(.text+0x1ef): undefined reference to `DirectFBErrorFatal'
Test01HorizontalLine.cpp:(.text+0x26d): undefined reference to `DirectFBErrorFatal'
/tmp/cc6iUS1W.o:Test01HorizontalLine.cpp:(.text+0x2e4): more undefined references to `DirectFBErrorFatal' follow
collect2: ld returned 1 exit status

Answer 1

你能试试这个吗?因为我现在没有这样的版本。

dsc.caps = DFBSurfaceCapabilities(DSCAPS_PRIMARY | DSCAPS_FLIPPING);  
...  
primary->Flip(primary, NULL, DFBSurfaceFlipFlags(0));  

Answer 2

如果您在项目中使用库，则包含标头的工作仅占工作的一半。您还必须显示实际库(libdirectfb.so (在您的情况下)位于何处，以便可以链接到您的代码。为此，可以传递-L和-l选项(注意，不需要前缀lib-或externsion .so )：

g++ your_source_file.cpp -I /path/to/include -L/path/to/lib -ldirectfb

有许多关于如何在项目中使用库的主题，即您可能希望启动这里和这里。

使用-Wall选项来查看更多关于正在发生的事情的信息总是一个好主意。