There are 2 ways to do this: Variadric macro #define my_printf(…) printf(__VA_ARGS__) function that forwards va_args #include <stdarg.h> #include <stdio.h> void my_printf(const char *fmt, …) { va_list args; va_start(args, fmt); vprintf(fmt, args); va_end(args); } There are also vsnprintf, vfprintf and whatever you can think of in stdio.
This does not answer the originally posed question, but if you are a programmer working with similar issues, this answer might help you. I really don’t see where the perceived difficulty is. Providing strict IEEE-754 binary64 semantics while being limited to 80387 floating-point math, and retaining 80-bit long double computation, seems to follow well-specified C99 … Read more
The standard says that SIZE_MAX must be at least 65535. It specifies no upper bound, and gcc’s implementation is perfectly valid. Quoting the reference you cited (emphasis added): Its implementation-defined value shall be equal to or greater in magnitude (absolute value) than the corresponding value given below, with the same sign.
Anonymous unions are a GNU extension, not part of any standard version of the C language. You can use -std=gnu99 or something like that for c99+GNU extensions, but it’s best to write proper C and not rely on extensions which provide nothing but syntactic sugar… Edit: Anonymous unions were added in C11, so they are … Read more
The expression f() + g() contains a minimum of 4 sequence points; one before the call to f() (after all zero of its arguments are evaluated); one before the call to g() (after all zero of its arguments are evaluated); one as the call to f() returns; and one as the call to g() returns. … Read more
It depends on what you mean by ‘truly standards compliant’. However, the short answer is “it is a good idea to ensure that all functions have a prototype in scope before being used”. A more qualified answer notes that if the function accepts variable arguments (notably the printf() family of functions), then a prototype must … Read more
The question is a bit old, but I figured I would take the time to link to my smart pointer library for GNU compilers (GCC, Clang, ICC, MinGW, …). This implementation relies on the cleanup variable attribute, a GNU extension, to automatically free the memory when going out of scope, and as such, is not … Read more
There are a bunch of incompatibilities that have been around for ages (C90 or earlier), as well as a bunch of really nice features in C99 and C11. These are all off the top of my head. // Valid C int *array = malloc(sizeof(*array) * n); // Valid C and valid C++, extra typing, it’s … Read more
the prior value shall be read only to determine the value to be stored. This is a bit vague and caused confusion, which is partly why C11 threw it out and introduced a new sequencing model. What it is trying to say is that: if reading the old value is guaranteed to occur earlier in … Read more
What C standard library functions are used inappropriately/in ways that may cause/lead to security problems/code defects/inefficiencies ? I’m gonna go with the obvious : char *gets(char *s); With its remarkable particularity that it’s simply impossible to use it appropriately.