embedded

问题 In C, the register storage qualifier is an hint to the implementation that such identifier should be accessed as fast as possible (e.g. stored in a CPU register). §6.7.1 A declaration of an identifier for an object with storage-class specifier register suggests that access to the object be as fast as possible. The extent to which such suggestions are effective is implementation-defined. and §6.7.3 The intended use of the restrict qualifier (like the register storage class) is to promote

问题 I'm starting a new project that has to convert data from XML to db . XMLs have their own format and cannot be used to fill a db . I choose to use sqlite , because it is an embedded platform and I need a lightweight library. I'm struggling with columns types. I wrote the sql below: static int callback(void *NotUsed, int argc, char **argv, char **azColName) { int i; for(i=0; i<argc; i++){ printf("%s = %s\n", azColName[i], argv[i] ? argv[i] : "NULL"); } printf("\n"); return 0; } static bool exec

问题 I am looking for a solution to the following problem: a C++ software module is developed that runs on an embedded device (no possibility to use the file based function "dlopen" to load shared libraries), while the module is running it shall be extendable by dynamic program code the dynamic code is written (realization of interface functions) and cross compiled (gcc) on a PC system before it is sent via a bus system to the previously described software module running on the embedded device the

问题 I want to know how i can create and use a new C library in lua 5.2.3. I can't use dynamic library (require, shared library, ...) due to I am on an embedded system. I found an answer but it is for lua 5.0 (http://www.lua.org/pil/26.2.html) and so it is not compatible. If someone have a idea ? 回答1: Edit linit.c and add your library entry point to it. Then add the modified linit.c to your project. The linker will use your copy instead of the one in the Lua library. This assumes your app calls

问题 The common implementation for MD5 is given by RFC1321. Where the MD5Update function receive a pointer to chars . My architecture, a SHARC ADSP-21371, is not byte adressable which means: sizeof(int32_t) == 1 Thus I cannot really use this algorithm as is. I need to wrap some complexity to unpack each int32_t data. Is there an alternative solution that I can use out of the box and if possible compatible C99 or C11? 回答1: I finally implemented MD5 for a octet-addressable architecture, here is for

问题 In C, I have read that half-initialized arrays will be filled with zeros for the rest of the elements (irrespective of integer or char arrays). E.g.: int arr[10] = {3}; arr[4] will be 0 if initialized and a junk value if not initialized. My question is, will the above work for all C compilers (or) this appending of zeros might occur or not occur depending on the compiler option? I am working in Code composer studio (TI's IDE). I want to ensure that this will work for all cases and all

问题 I'm trying to make "Blinky" for STM32F1xx in Rust. I know that there are libs for it, but I want to make my own "lib" for learning purposes. I can access STM32's "registers" by their addresses like this in C: *(uint32_t*)(0x40021000 + 0x018) |= 0x10; *(uint32_t*)(0x40011000 + 0x004) |= 0x33; *(uint32_t*)(0x40011000 + 0x004) &= ~0xCC; *(uint32_t*)(0x40011000 + 0x10) |= 0x300; while(1) {} This writes some bits to the RCC_APB2ENR register to enable clocking of port C, configures pins and enables

问题 I often see such representation of MAC address in C code: struct mac_addr { unsigned char bytes[6]; } Why necessary put an array in a structure, why not just have an array? What benefit does this provide? Thanks. 回答1: You can't assign an array in C. But you can assign a struct. 来源： https://stackoverflow.com/questions/19482750/representation-of-mac-address-in-c-code

问题 I have been using an embedded activeMQ server configuration (configuration is very similar to the examples that illustrate the concept of an embedded activeMQ server/listener). Aas part of the application, I have a monitoring thread that monitors a directory. Instead of having to kill the process to shutdown the activeMQ server, I introduced a check for a "STOP" file and if the file exists, the server would shutdown. The shutdown I am trying to accomplish by calling the stop function on the

问题 I am going to setup build environment to make my own linux embedded system for AT91SAM9X25 Board. I am using buildroot to do this. The make command build all targets, the first it build toolchain then packages and then rootfs and images of rootfs (tar, cpio ...). To rebuild rootfs I usually use make clean and then make. The make clean command removes all and including toolchain. So the first my question is: Is there some way to remake rootfs without building toolchain? It takes a lot of time.