printf() output is only displayed if the kernel finishes successfully, so check the return codes of all CUDA function calls and make sure no errors are reported. Furthermore printf() output is only displayed at certain points in the program. Appendix B.32.2 of the Programming Guide lists these as Kernel launch via <<<>>> or cuLaunchKernel() (at … Read more
As this error states, you cannot implement a trait for a type you don’t own: the impl does not reference any types defined in this crate; only traits defined in the current crate can be implemented for arbitrary types However, you can implement Display for your wrapper type. The piece you are missing is to … Read more
You didn’t say exactly what the problem you’re seeing is, but I’m guessing that you’re crashing at the point of the call to printf. This is because OS X (both 32- and 64-bit) requires that the stack pointer have 16-byte alignment at the point of any external function call. The stack pointer was 16-byte aligned … Read more
sprintf() returns a string, printf() displays it. The following two are equal: printf(currentDateTime()); print sprintf(currentDateTime());
Why is printf(“%8d\n”, intval); not working for you? It should… You did not show the format strings for any of your “not working” examples, so I’m not sure what else to tell you. #include <stdio.h> int main(void) { int i; for (i = 1; i <= 10000; i*=10) { printf(“[%8d]\n”, i); } return (0); } … Read more
With the %f format specifier, the “2” is treated as the minimum number of characters altogether, not the number of digits before the decimal dot. Thus you have to replace it with 4 to get two leading digits + the decimal point + one decimal digit. printf(“%d:%02d:%04.1f hours\n”, 1, 4, 2.123456);
In C++20 you can use std::format for safe printf-like formatting: std::cout << std::format(“The answer is {}.\n”, 42); In addition to that the {fmt} library, std::format is based on, provides the print function that combines formatting and output: fmt::print(“The answer is {}.\n”, 42); Disclaimer: I’m the author of {fmt} and C++20 std::format.
The code will probably print “ciao” twice as standard output is buffered IO so the internal buffer for standard output will be replicated in the child process and both buffers flushed when each process, the parent and child, exits. It is unrelated to optimization.
Your program will compile fine, as printf() is a variadic function and the matching check of the number of format specifiers with supplied argument is not performed by default. At runtime, your program exhibits undefined behaviour, as there in no argument supplied which has to be printed using the supplied format specifier. As per chapter … Read more
%d stands for decimal and it expects an argument of type int (or some smaller signed integer type that then gets promoted). Floating-point types float and double both get passed the same way (promoted to double) and both of them use %f. In C99 you can also use %lf to signify the larger size of … Read more