如题,不支持MMU的实时操作系统如uC/OS II或FreeRTOS,多任务是指同一时刻只有一个任务可以运行,那么在不带MMU的前提下,可不可以设计出一个多任务并发的操作系统,即同一时刻有多个任务运行?各个任务之间如何做到数据保护?如果只是机械地分布到不同的物理地址上,是不是有点生硬?
在各种编程语言中,调用获取系统时间的API来获取当下系统时间,都说是从1970/01/01 00:00:00算起,这是为啥?是操作系统诞生元年?那么windows和unix?还是和计算机的硬件处理器芯片正式通电工作有现代计算机工作雏形有关?
Android编译的时候宏定义PRODUCT_ENFORCE_VINTF_MANIFEST是哪里配置的,找了好久没找到
报错内容:CameraBin error: "Internal data stream error." 不知道是什么原因
Checking for ffmpeg/libavcodec/allcodecs.c ... found Checking for ffmpeg/libavcodec/hwaccels.h ... found Checking for ffmpeg/libavformat/allformats.c ... found Checking for ffmpeg/libavcodec/bitsteram_filters.c ... found Checking for ffmpeg/libavformat/protocols.c ... found Checking for ffmpeg/libavfilter/allfilters.c ... found Checking for gcc version ... 5.4.0 Checking for working compiler ... yes Detected operating system: Linux Detected host architecture: arm Checking for cross compilation ... no Checking for host cc ... gcc Checking for byte order ... little-endian Checking for extern symbol prefix ... Checking for assembler support of -pipe option ... yes Checking for relocatable binary ... no (unavailable or untested architecture) Checking for PIC ... no Checking for ARMv5TE (Enhanced DSP Extensions) ... no Checking for ARMv6 (SIMD instructions) ... no Checking for ARMv6t2 (SIMD instructions) ... no Checking for ARM VFP ... no Checking for ARM VFPV3 ... no Checking for ARM setend ... no Checking for softfloat ABI ... no Checking for ARM NEON ... no Checking for ARM THUMB ... no Checking for iWMMXt (Intel XScale SIMD instructions) ... no Checking for langinfo ... no Checking for language ... messages: en - man pages: en - documentation: en Checking for enable sighandler ... yes Checking for runtime cpudetection ... no Checking for restrict keyword ... none Checking for __builtin_expect ... no Checking for kstat ... no Checking for atanf ... no Checking for cbrt ... no Checking for cbrtf ... no Checking for cosf ... no Checking for expf ... no Checking for exp2 ... no Checking for exp2f ... no Checking for isnan ... no Checking for isfinite ... no Checking for isinf ... no Checking for llrint ... no Checking for llrintf ... no Checking for log2 ... no Checking for log2f ... no Checking for log10f ... no Checking for lrint ... no Checking for lrintf ... no Checking for rint ... no Checking for round ... no Checking for roundf ... no Checking for sinf ... no Checking for trunc ... no Checking for truncf ... no Checking for erf ... no Checking for atan2f ... no Checking for fminf ... no Checking for ldexpf ... no Checking for powf ... no Checking for hypot ... no Checking for mkstemp ... no Checking for gmtime_r ... no Checking for localtime_r ... no Checking for nanosleep ... no Checking for socklib ... no Checking for struct pollfd ... no Checking for netdb.h struct addrinfo ... no Checking for netdb.h getaddrinfo() ... no Checking for sockaddr_storage ... no Checking for struct ipv6_mreq ... no Checking for struct sockaddr_in6 ... no Checking for struct sockaddr sa_len ... no Checking for arpa/inet.h ... no Checking for inet_pton() ... no Checking for inet_aton() ... no Checking for socklen_t ... no Checking for closesocket() ... no Checking for networking ... no Checking for inet6 ... no Checking for gethostbyname2 ... no Checking for SCTP ... no Checking for sys/un.h ... no Checking for sys/poll.h ... no Checking for inttypes.h (required) ... no Checking for sys/bitypes.h (inttypes.h predecessor) ... Error: Cannot find header either inttypes.h or bitypes.h. There is no chance for compilation to succeed. Check "config.log" if you do not understand why it failed. 出现了这种错误,网上资料很少请各位大佬知道
有个细节问题一直不太理解Linux设备驱动里面经常看到pdev->dev.parent这个pdev dev 和parent分别指代什么的
请大佬指点 本人想通过QT编写串口通信,想在qt上的页面发送“1”,实现红灯亮,发送“0”,实现红灯灭,发送“开启”,绿灯亮,发送“关闭”,绿灯灭,通过stm官网的串口助手,已经实验控制灯的亮灭,但是在QT上面不能实现。 if(USART_RX_STA &0x8000 ) { USART_RX_STA = 0; if(USART_RX_BUF[0] == '1') { LED0 = 1; } if(USART_RX_BUF[0] == '0') { LED0 = 0; } { LED1=0;//PC13 } if(!(strcmp(USART_RX_BUF"开启"))) { LED1=1; }