c - 为什么我的简单 GLX 应用程序会泄漏内存？

Question

下面的代码显示了 valgrind 中的一个小的 48 字节泄漏。

#include <X11/Xlib.h>
#include <GL/glx.h>
#include <unistd.h>

int main( int argc, char* argv[] )
{
    Display* _display;
    Window _windowHandle;
    XVisualInfo* _visual;
    GLXContext _context;
    Atom _deleteWindowMessage;
    Atom _pingWindowMessage;

    _display = XOpenDisplay( NULL );

    int attributes[] = { GLX_RGBA,
                         GLX_DOUBLEBUFFER,
                         GLX_RED_SIZE, 8,
                         GLX_BLUE_SIZE, 8,
                         GLX_GREEN_SIZE, 8,
                         GLX_ALPHA_SIZE, 8,
                         GLX_DEPTH_SIZE, 8,
                         GLX_STENCIL_SIZE, 0,
                         0 };

    _visual = glXChooseVisual( _display, 
                               DefaultScreen( _display ),
                               attributes );

    _context = glXCreateContext( _display,
                                 _visual,
                                 0,
                                 GL_TRUE );

    Colormap colormap;

    colormap = XCreateColormap( _display, 
                                RootWindow( _display, _visual->screen ),
                                _visual->visual,
                                AllocNone );

    XSetWindowAttributes windowAttributes;

    windowAttributes.colormap = colormap;
    windowAttributes.border_pixel = 0;
    windowAttributes.event_mask = ExposureMask | StructureNotifyMask;


    _windowHandle = 
        XCreateWindow( _display,
                       RootWindow( _display, _visual->screen ),
                           0, 
                           0,
                           1280, 
                           720,
                           0,                      // Borderwidth
                           _visual->depth,         // Depth
                           InputOutput,
                           _visual->visual,
                           CWBorderPixel | CWColormap | CWEventMask,
                           &windowAttributes );
    XFreeColormap( _display, colormap );


    XMapWindow( _display, _windowHandle );

    // causes 48 byte leak...
    glXMakeCurrent( _display,
                    _windowHandle,
                    _context );

    sleep( 3 );

    XUnmapWindow( _display, _windowHandle );


    XDestroyWindow( _display, _windowHandle );


    glXMakeCurrent( _display, 
                    None,
                    NULL );

    glXDestroyContext( _display, _context );

    XFree( _visual );

    XCloseDisplay( _display );

    return 0;
}

这段代码所做的只是为 GLX 渲染初始化一个窗口，然后将其拆除。有趣的是，当我调用 glXMakeCurrent() 时，我泄漏了 48 个字节...... valgrind 输出如下所示:

[developer@localhost ~]$ valgrind --tool=memcheck --leak-check=full ./simplex
==9531== Memcheck, a memory error detector
==9531== Copyright (C) 2002-2009, and GNU GPL'd, by Julian Seward et al.
==9531== Using Valgrind-3.5.0 and LibVEX; rerun with -h for copyright info
==9531== Command: ./simplex
==9531== 
==9531== 
==9531== HEAP SUMMARY:
==9531==     in use at exit: 248 bytes in 6 blocks
==9531==   total heap usage: 1,265 allocs, 1,259 frees, 2,581,764 bytes allocated
==9531== 
==9531== 48 bytes in 1 blocks are definitely lost in loss record 5 of 6
==9531==    at 0x400591C: malloc (vg_replace_malloc.c:195)
==9531==    by 0x349D0F8: ??? (in /usr/lib/nvidia/libGL.so.180.60)
==9531== 
==9531== LEAK SUMMARY:
==9531==    definitely lost: 48 bytes in 1 blocks
==9531==    indirectly lost: 0 bytes in 0 blocks
==9531==      possibly lost: 0 bytes in 0 blocks
==9531==    still reachable: 200 bytes in 5 blocks
==9531==         suppressed: 0 bytes in 0 blocks
==9531== Reachable blocks (those to which a pointer was found) are not shown.
==9531== To see them, rerun with: --leak-check=full --show-reachable=yes
==9531== 
==9531== For counts of detected and suppressed errors, rerun with: -v
==9531== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 30 from 8)

如果你在 sleep 之前注释掉对 glXMakeCurrent() 的调用，泄漏就会消失......当然，我需要进行该调用才能渲染任何东西!

真正的问题是我的应用程序创建了许多子窗口，每个子窗口都关联了 GLX 上下文......并且每个都泄漏了相同的 48 字节......我不知道还能尝试什么(代码正在清理 GLX上下文)...有什么想法吗？

Answer 1

好的，看来真的没有漏水

Valgrind 仍在报告泄漏，但我编写了一个测试应用程序，它在随机位置显示了数千个窗口，并且内存通过顶部完全平坦...所以，看起来我需要一个用于 glx 应用程序的抑制文件.