compiler-warnings

I'm trying to use one of the simplest forms of reflection to create an instance of class: package some.common.prefix; public interface My { void configure(...); void process(...); } public class MyExample implements My { ... // proper implementation } String myClassName = "MyExample"; // read from an external file in reality Class<? extends My> myClass = (Class<? extends My>) Class.forName("some.common.prefix." + myClassName); My my = myClass.newInstance(); Typecasting unknown Class object we've got from Class.forName yields a warning: Type safety: Unchecked cast from Class<capture#1-of ?> to

As advised by an answer here, I turned on -Wbad-function-cast to see if my code had any bad behavior gcc could catch, and it turned up this example: unsigned long n; // ... int crossover = (int)pow(n, .14); (it's not critical here that crossover is an int ; it could be unsigned long and the message would be the same). This seems like a pretty ordinary and useful example of a cast. Why is this problematic? Otherwise, is there a reason to keep this warning turned on? I generally like to set a lot of warnings, but I can't wrap my mind around the use case for this one. The code I'm working on is

When I executed the code of this question , I got this warning: warning: format '%d' expects argument of type 'int', but argument 2 has type 'long int' [-Wformat=] printf("P-Q: %d, P: %d, Q: %d", (p - q), p, q); ~^ ~~~~~~~ %ld As a reflex fix, I used %ld to print the subtraction of two pointers. And the compiler agreed. Fortunately, I saw a comment from another user mentioning that %td should be used, since the result type of the subtraction is ptrdiff_t . This answer confirms this claim. Now from GCC's header file of stddef.h , I can see that these types are equivalent in this case: typedef _

When I do this: count = ++count; Why do i get the warning - The assignment to variable count has no effect ? This means that count is incremented and then assigned to itself or something else ? Is it the same as just ++count ? What happens in count = count++; ? Why don't I get a warning for this ? count++ and ++count are both short for count=count+1 . The assignment is built in, so there's no point to assigning it again. The difference between count++ (also knows as postfix ) and ++count (also known as prefix ) is that ++count will happen before the rest of the line, and count++ will happen

I want to see all compiler warnings in CLion. I don't want them treated as errors, but I want to inspect all of them. How can I do this? Gluttton Try to set compiler flag in CMakeLists.txt : set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra") Related question: How to enable C++11 in CLion? Rebuild your entire project. Most compilers don't rebuild every file when you just press build, so you will only see warnings from files that were changed. For C: set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra") 来源： https://stackoverflow.com/questions/31790467/how-to-enable-all-compiler-warnings-in

c++ Builder xe5 [ilink32 Error] Error: Unable to perform link [ilink32 Warning] Warning: Error detected (LME288) that happened when i tried to compile a test project c++ builder xe5 on windows xp Barry Andrews I got some information on this from Embarcadero which may help. The error is an "out of memory", error. The reason for "Out Of Memory" errors (which come in different guises) in the linker, is that the linker has to pre-allocate memory in contiguous heaps that it then uses as it links, in the past these heaps could not be adjusted, we had to do a best guess, so in the new 64-bit linker

I know that one should always compile with both -Wall and -Wextra as they enable warnings and help us to understand our mistake, if any. I've read that the -Wextra compiler flag is not recommended to use because it is too verbose with a lot of false positives. I was quite surprised on reading this. So I started googling about it but I didn't get any answer as all the search results showed was "what does the -Wextra flag do?". So, my questions are In which all situations does the -Wextra flag emit uneccessary warnings? Is it possible to stop the -Wextra flag from enabling the other flags that

Typing man strptime it sais that this function needs to have declared _XOPEN_SOURCE and included time.h header. I did it. But, when I try to compile my code I get: ./check.c:56: warning: implicit declaration of function ‘strptime’ Look at my code: int lockExpired(const char *date, const char *format, time_t current) { struct tm *tmp = malloc(sizeof(struct tm *)); time_t lt; int et; strptime(date, format, tmp); lt = mktime(tmp); et = difftime(current, lt); if (et < 3600) return -et; return 1; } Also the function declaration is: char *strptime(const char *s, const char *format, struct tm *tm);