How to get main() function return value in Linux terminal.

Sometimes we want to get the exit value of main() function, using the "echo $? " can get the most recently program exit value.

Example program:

Result:

Reference:
  1. UNIX Shell Programming 

C : strrchr() analyze and example get self executable directory function.

strrchr() function will return a pointer to the last occurrence.
Another example is modify from Advanced Linux Programming chapter 11.We can get a sub-sting without the occurrence with sub two pointer.





Ref:
   1. http://www.cplusplus.com/reference/cstring/strrchr/
   2. Advanced Linux Programming by Mark Mitchell, Jeffrey Oldham, and Alex Samuel www.newriders.com

Keil C: Warning: #1296-D: extended constant initialiser used"?

The root cause is miss use a pointer to a static variable like:

int x = 1;
int y = (int) &x;

Modify version

int x = 1;
int *y = &x;

printf("%p\n", &x);  // memory address of x
printf("%p\n", &y);   // memory address of y

printf("%p\n", y);     // y = memory address of x
printf("%d\n", *y);   // *y = memory content of x  = 1


Addresses are not arithmetic types in ANSI C spec, so if need to get the address of a static variable, use a pointer point to the variable's address.







Ref :
 1. http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.faqs/ka15182.html
 2.https://openhome.cc/Gossip/CGossip/Pointer.html

CC2640: Bus fault exception error on AuxAdiDdiSafeWrite function

Temporary solution : Disable the Power Saving feature on your project and rebuild both stack and app project.

My BLE stack version is 2_02_01_18, TI RTOS CC26xx version is 2_20_01_18,  XDC tool version is 3_32_00_06

I guess the reason of this error is cause by the power constrain setting and peripheral issue, because the power initial code in [9],  but I am not very sure since I didn't go deep in this problem now.








 Some related source:
    1.CC26XX Driver lib document:AuxAdiDdiSafeWrite 
    2.CC2640: Bus fault after random number of packets received to cc2640
    3.CC2650调试问题
    4.CC2640 - Sensor Controller power consumption
    5.hard fault in CC3200 I2C
    6.I2C Peripheral Setup Causes a processor Force Hardware Fault
    7.RTOS/CC2640: Hard Fault: FORCED: BUSFAULT: PRECISERR.Data Access Error.
    8.Hard Fault: FORCED: BUSFAULT: PRECISERR.Data Access Error
    9.CC2650 as I2C Slave

Reason?

1. CC2640如何在打开PowerSaving模式下唤醒并操作uart？
2. RTOS/CC2640: Unresponsive in power saving mode
3. CC2640 UART With Power Saving
4. Power Managementfor CC26xx SimpleLink Wireless MCUsUser’s Guide
5. Where and why the SMPH0 reset error (keep 0) did not release

Unsigned and signed shift:logical shift and arithmetic shift

In C, we usually use left shift and right shift operation << and >> to operate multiple / divide to variable with power of 2,ex: 4<<2  = 16

But when we use the signed variable and the shift operation we must consider the singed bit.See the below example code.

Since the C language support the arithmetic left shift and logic right shift,  we must consider the signed bit to  avoid some bug in code.



Ref:
     1.Logical Vs. Arithmetic Shift
     2.C语言中的逻辑右移和算术左移

CC2640: Merge app and stack hex file

1. Install Python2.7
2. Open cmd.exe type > pip install intelhex
 

3. Use below instruction to merge your hex file

Ref:
      1.CC26x0 SimpleLink™ Bluetooth® low energy Software Stack 2.2.x Developer's Guide
         section 2.6

GO: Development a simple windows GUI use lxn-walk package(2) -- Combobox and Button

1.Create the project folder and win_gui_v1.go in your go work space
   > cd ..\src\
   > mkdir win_gui_v1
2.Copy the .manifest file and modify to your_execution.exe.manifest
 

3.Code
3.Result

 











Ref:
      1. Go实战--使用golang开发Windows Gui桌面程序(lxn/walk)
      2. ComboBox 類別
      3. lxn/walk/examples