android emulator

set ANDROID_ADB_SERVER_PORT=50037
emulator.exe -list-avds
emulator -avd Copy_of_New_Device_API_30 -netdelay none -netspeed full   -grpc-use-token -idle-grpc-timeout -wipe-data

qtableview row height

Qtableview headerview setdefaultsectoion无效：需要设置headerview的minimumSectionSize，maximumSectionSize 然后调用qtableview的setrowheight,这个函数内部调用的是headerview的resizesection

QHeaderView bounds the value passed to setDefaultSectionSize so you might need to call setMinimumSectionSize and setMaximumSectionSize before setting the default size. horizontalHeader()->setStretchLastSection(true);

cut and paste clipboard exchange between Qt application and Windows Explorer

cut and paste clipboard exchange between Qt application and Windows Explorer

phy dts document

Documentation\devicetree\bindings\net

ref

&fec2 {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_enet2
				&pinctrl_enet2_reset>;
	phy-mode = "rmii";
	phy-handle = <&ethphy1>;
	phy-reset-gpios = <&gpio5 8 GPIO_ACTIVE_LOW>;
	phy-reset-duration = <200>;
	status = "okay";

	mdio {
		#address-cells = <1>;
		#size-cells = <0>;

		ethphy0: ethernet-phy@0 {
		compatible = "ethernet-phy-ieee802.3-c22";
		smsc,disable-energy-detect;
		reg = <0>;
		};
 
		ethphy1: ethernet-phy@1 {
        	compatible = "ethernet-phy-ieee802.3-c22";
		smsc,disable-energy-detect;
        	reg = <1>;
		};
	};

reg表示phy的物理地址，由硬件给定。

Kernel oops when remounting ubifs as read/write

kernel oops when remounting ubifs as read/write

ubi文件系统第一次启动uboot通过ro加载,如果进行remount会导致crc校验出错。解决方案是uboot先用rw加载，然后再通过mount -o 'remount,ro'命令修改为ro

按这个分析应该是内核的bug, 目前使用的内核是3.几的

drop caches

echo 1 >> /proc/sys/vm/drop_caches

error c2332 struct 缺少标记名

error c2332 struct 缺少标记名 变量名和关键字冲突了。这次是遇到的是interface在msvc中冲突了。。。可是c++没有interface这个关键字

https://stackoverflow.com/questions/25234203/what-is-the-interface-keyword-in-msvc

Microsoft has some compiler-specific extensions like the one you linked but interface shouldn't be a native C++ compiler-specific keyword but rather a define which substitutes something (in BaseTyps.h it used to be defined as follows)

define interface struct

Link here If you want to verify this do a grep for such a definition and you should find something similar.

References: http://social.msdn.microsoft.com/forums//vstudio/en-US/06bf1dea-1d20-4ec3-b9a1-3d673d7fcd8d/what-is-the-interface-keyword-in-native-c

qprocess::execute执行date命令失败

但是自己通过命令行可以执行，通过strace跟踪系统调用：

strace -f -F -p 980

发现：

execve("/dymind/lib/cups/sbin/date", ["date", "-s", "2024-09-15 17:12:37"], [/* 26 vars */] <u <... execve resumed> )  = -1 EIO (Input/output error)

所以认为是磁盘损坏导致的。因为损坏导至dymind/lib/cups/sbin这个目录无法读取，所以system调用直接返回失败了，没有做更多的偿试。

一种定位内存泄漏方法：

内存泄漏肯定是堆上的内存，那么我们找到进程的heap内存区，然把这块内存通过gdb dump到 文件，然后在这个文 件中查找出现次数最多的文本。

$ grep heap /proc/1131/maps
00c7d000-00d94000 rw-p 00000000 00:00 0         [heap]
dump binary memory /tmp/heap.bin 0x00c7d000 0x00d94000

这种方法可以定位内存中有一致的字符串的情况。 在分析dbus的内存泄漏时，使用这种方法， 发现内存中出现了大量的wifi搜过结果。 确定了是dbus模块内存泄漏，通过查看代码发现一处dbus缺少endarray调用，修改后内存正常。