「programming」カテゴリーアーカイブ

pointer to 2-d array

2021年10月1日debian、programmingkiyoshi

Suppose: float buff[10][20];
float (*m_ptr)[10][20] = &buff;
Can access: (*m_ptr)[0][1]= …; w=(*m_ptr)[0][1];
My practice:

in global.h
firbuftk[2][3]; unsigned firbuftk_index; float (*m_ptr)[2][3] = &firbuftk;
firbuftk_index is not necessarily needed.

AVR Dragon on Kiyoshi(xp)

2019年5月2日NDOT、NSDOT、programmingkiyoshi

Connect AVR Dragon (Parallel wiring intact, ISP 2pin 5V wired): big Red, small Green lit. AVR Dragon is on the device manager: Jungo section. Yet cannot open usb connection on Flip3.3.4.
AVR studio4: debugplatform:AVR Dragon, Device ATmega164P:finish;
Tools->Program AVR->(Select AVR programmer)AVR Dragon, usb: ->connect
(source file should be selected):window(AVR Dragon in PP/HVSP mode with ATmega164P) will popup.
Click necessary action, checking the messages OK!.

“source” in shell script

2018年11月28日debian、programmingkiyoshi

“source” command cannot work in shell script.

Instead:

$source the shell script file;

will work. Or

$. shell-script-file

should work.

errno in linux

2015年4月4日programmingkiyoshi

#include <errno.h>

if(clock_gettime(CLOCK_MONOTONIC_RAW, tp)!=0)
printf(“errno=%d: %s\n”, errno, strerror(errno));

(not so good example)

clock() etc. in linux

2015年4月1日programmingkiyoshi

secs = (clock() – ut0)/(double)CLOCKS_PER_SEC; will overflow every72 minutes in 32 bit machine.

clock_gettime(CLOCK_REALTIME, tp) may be most modern, but needs -lrt when linking.

make trouble

2014年2月24日programmingkiyoshi

Try : make clean

gtk

2013年12月15日debian、programmingkiyoshi

gtk_widget_size_request may cause segmentation fault