Look at the grammar for the C language. It’s listed, in full, in Appendix A of the standard. The way it works is that you can step through each token in a C program and match them up with the next item in the grammar. At each step you have only a limited number of … Read more
For dense packing that doesn’t incur a large overhead of reading, I’d recommend a struct with bitfields. In your example where you have four values ranging from 0 to 3, you’d define the struct as follows: struct Foo { unsigned char a:2; unsigned char b:2; unsigned char c:2; unsigned char d:2; } This has a … Read more
It wouldn’t. The two fundamental issues with global variables is simply cluttering the namespace, and the fact that “no one” has “control” over them (thus the potential collisions and conflict with multiple threads). The “globals are bad”, like pretty much every other computer programming idiom is a guideline, not a hard and fast rule. When … Read more
Only pointers can be null. CGRect is a struct – it represents a contiguous block of memory. The only way to tell if it has been set it to check its contents. Apple does provide a constant CGRectNull. You could set your variable to this and use the CGRectIsNull function to determine if it has … Read more
The following code will give you a hex dump of arbitrary memory from within your code. #include <stdio.h> // Usage: // hexDump(desc, addr, len, perLine); // desc: if non-NULL, printed as a description before hex dump. // addr: the address to start dumping from. // len: the number of bytes to dump. // perLine: number … Read more
tl;dr -> Provide a proper MVCE. This answer should be a comment but is too big to be posted as comment, so posting as answer instead: I had to fix a bunch of syntax errors (missing semicolons) and declare undefined variables. After fixing all those problems, the code did NOTHING (the program quit even prior … Read more
I don’t have an answer about how to do this with Boehm. However, here are two GCs which seem to have enough control and encapsulation to have a totally independent GC context per-thread. Lua’s Garbage Collector – MIT Steve Dekorte’s libgarbagecollector – BSD
IMO, code like argv[1] = “123”; is UB (using the original argv). “The parameters argc and argv and the strings pointed to by the argv array shall be modifiable by the program, and retain their last-stored values between program startup and program termination.” C11dr & C17dr1 ยง5.1.2.2.1 2 Recall that const came into C many … Read more
Googled it.Found some links.They seem helpful : redhat.com –Debugging programs with multiple threads Multi-threaded Debugging Techniques
struct addrinfo is returned by getaddrinfo(), and contains, on success, a linked list of such structs for a specified hostname and/or service. The ai_addr member isn’t actually a struct sockaddr, because that struct is merely a generic one that contains common members for all the others, and is used in order to determine what type … Read more