printf

问题 I'm struggling to properly implement printf from newlib into my esp32, using GCC. I've gone through the newlib documentation and it gives me general information about how printf is called, but doesn't explain the back end implementation to me. Based on my current research I have determined that printf outputs a formatted string to the STDOUT. On a PC this was simpler for me to understand because there's a console window that would display the formatted output from printf, however on an

问题 I'm struggling to properly implement printf from newlib into my esp32, using GCC. I've gone through the newlib documentation and it gives me general information about how printf is called, but doesn't explain the back end implementation to me. Based on my current research I have determined that printf outputs a formatted string to the STDOUT. On a PC this was simpler for me to understand because there's a console window that would display the formatted output from printf, however on an

问题 Take the following : #include <stdio.h> main() { unsigned long long verybig = 285212672; printf("Without variable : %llu\n", 285212672); printf("With variable : %llu", verybig); } This is the output of the above program : Without variable : 18035667472744448 With variable : 285212672 As you can see from the above, when printf is passed the number as a constant, it prints some huge incorrect number, but when the value is first stored in a variable, printf prints the correct number. What is the

问题 Take the following : #include <stdio.h> main() { unsigned long long verybig = 285212672; printf("Without variable : %llu\n", 285212672); printf("With variable : %llu", verybig); } This is the output of the above program : Without variable : 18035667472744448 With variable : 285212672 As you can see from the above, when printf is passed the number as a constant, it prints some huge incorrect number, but when the value is first stored in a variable, printf prints the correct number. What is the

问题 Take the following : #include <stdio.h> main() { unsigned long long verybig = 285212672; printf("Without variable : %llu\n", 285212672); printf("With variable : %llu", verybig); } This is the output of the above program : Without variable : 18035667472744448 With variable : 285212672 As you can see from the above, when printf is passed the number as a constant, it prints some huge incorrect number, but when the value is first stored in a variable, printf prints the correct number. What is the

问题 Take the following : #include <stdio.h> main() { unsigned long long verybig = 285212672; printf("Without variable : %llu\n", 285212672); printf("With variable : %llu", verybig); } This is the output of the above program : Without variable : 18035667472744448 With variable : 285212672 As you can see from the above, when printf is passed the number as a constant, it prints some huge incorrect number, but when the value is first stored in a variable, printf prints the correct number. What is the

问题 Take the following : #include <stdio.h> main() { unsigned long long verybig = 285212672; printf("Without variable : %llu\n", 285212672); printf("With variable : %llu", verybig); } This is the output of the above program : Without variable : 18035667472744448 With variable : 285212672 As you can see from the above, when printf is passed the number as a constant, it prints some huge incorrect number, but when the value is first stored in a variable, printf prints the correct number. What is the

问题 Take the following : #include <stdio.h> main() { unsigned long long verybig = 285212672; printf("Without variable : %llu\n", 285212672); printf("With variable : %llu", verybig); } This is the output of the above program : Without variable : 18035667472744448 With variable : 285212672 As you can see from the above, when printf is passed the number as a constant, it prints some huge incorrect number, but when the value is first stored in a variable, printf prints the correct number. What is the

问题 I'm wondering why printf() when provided an array and no formatting options, successfully prints character arrays but while using integer arrays the compiler throws a warning and a garbage value is printed. Here's my code: #include <stdio.h> int main() { char cr[3] = { 'a', 'b' }; int ar[3] = { 1, 2 }; printf("character array output using printf() : "); printf(cr); printf("\n\nInteger array output using printf() : "); printf(ar); printf("\n"); return 0; } and here's my output: ../main.c: In

问题 here is a demo.cu aiming to printf from the GPU device: #include "cuda_runtime.h" #include "device_launch_parameters.h" #include <stdio.h> __global__ void hello_cuda() { printf("hello from GPU\n"); } int main() { printf("hello from CPU\n"); hello_cuda <<<1, 1>>> (); cudaDeviceSynchronize(); cudaDeviceReset(); printf("bye bye from CPU\n"); return 0; } it compiles and runs: $ nvcc demo.cu $ ./a.out that's the output that I get: hello from CPU bye bye from CPU Q: why there is no printing result