c99

问题 I often times write to memory mapped I/O pins like this P3OUT |= BIT1; I assumed that P3OUT was being replaced with something like this by my preprocessor: *((unsigned short *) 0x0222u) But I dug into an H file today and saw something along these lines: volatile unsigned short P3OUT @ 0x0222u; There's some more expansion going on before that, but it is generally that. A symbol '@' is being used. Above that there are some #pragma's about using an extended set of the C language. I am assuming

问题 I am using PC-Lint 8.00x with the following options: +v -wlib(1) +fan +fas I receive a number of error messages from PC-Lint when I run code similar to the following: typedef union { struct { unsigned int a : 4; unsigned int b : 4; unsigned int c : 4; unsigned int d : 4; } bits; unsigned short value; } My_Value; int main (void) { My_Value test[] = { { .bits.a = 2, .bits.b = 3, //Errors 133 and 10 .bits.c = 2, .bits.d = 3, }, { .bits.a = 1, .bits.b = 1, //Errors 133 and 10 .bits.c = 1, .bits.d

问题 I'd like to ensure that a given string literal ends up at an address that is a multiple of 2, or even better, 4. Is there any way to achieve that, preferably without using any compiler-specific extensions? Or is it impossible? I'd like to do this so the lowermost bits of the string address are 0 and can be (ab)used as tag bits. 回答1: In C99 you can do this using a union, for example #define ALIGNED_STR_UNION(N, S) const union { char s[sizeof S]; int align; } N = { S } ALIGNED_STR_UNION(sssu,

问题 CERT's Secure Coding Standard includes an item (API05-C) which encourages the use of conformant array parameters, which is a recommendation I've implemented in a lot of my code (hidden behind a macro for compilers which don't support them). For those who don't know, a conformant array parameter is something like: void foo(int length, char data[length]); API05-C provides more information. Lots of compilers don't like variable-length arrays (for good reason). C11 demotes them from required (as

问题 Why does the boolean type support introduced in C99 use the preprocessor rather than the language's own facilities? Specifically, why do we have: #define bool _Bool #define true 1 #define false 0 in <stdbool.h> rather than: typedef _Bool bool; enum { false = 0, true = 1 }; I guess the enum can be seen as a matter of taste. But - why not have a typedef? 回答1: From section 7.18/3 of the C11 specification: The remaining three macros are suitable for use in #if preprocessing directives. The

问题 Reading the POSIX reference for socket send at http://pubs.opengroup.org/onlinepubs/009695399/functions/send.html I wonder, what exactly do they mean by "byte" - its traditional/historical meaning, its implied/popular meaning, or something else entirely? I am developing a binary TCP/IP-supported network protocol client-server program, and I would like to properly declare my buffer that I use to pass to recv , and being able to properly unpack its data. Yes, I know it's almost hypothetical

问题 I'm using VS 2010. I have changed the settings for compiler C code instead of C++. It works fine, but the problem is MS compilers don't supports C99 standard,for this reason I'm looking for a C compiler that can works with VS 10. How to do this? Thanks in advance. 回答1: MS visual studio don't support c99, however they have implemented certain features of c99. From this Microsoft page, their reply for c99 support: Question by a user: "I would like to see C99 support available in Visual Studio.

问题 I have four different layers of struct nested. The code is as follows: typedef struct System system; typedef struct College college; typedef struct Student student; typedef struct Family family; #define MAX_COLLEGES 10 #define MAX_NAME_LEN 32 #define MAX_STUDENTS 10 struct System { college *Colleges[MAX_COLLEGES]; }; struct College { char name[MAX_NAME_LEN]; student *Students[MAX_STUDENTS]; }; struct Student { char name[MAX_NAME_LEN]; int id; family *fam; //was typo familiy }; struct Family {

问题 I am using the MinGW compiler for Windows. I am making some programs in C. Most of the articles I read up on this seem to be outdated... last I read C99 was incomplete in the GCC is this still true? My real question is cross platform compatibility between setting C99 and GNU99... should I avoid using GNU99 setting and it's extensions and just stick with C99? I am new to this MinGW compiler set as I have always used Visual Studio and decided to try something new... right now I am compiling

问题 I have records with flexible array member typedef struct record { unsigned foo; signed bar; double number[]; } record; I have multiple records with the same amount of numbers so I can arrange them in array. I would like to allocate them into one continuous memory space. const unsigned numbers = ...; const unsigned records = ...; const size_t record_size = sizeof(record) + numbers*sizeof(double); record *prec = malloc(records*record_size); So now I know record_size and I can access it but what