All Questions
134 questions
5
votes
1
answer
259
views
How do I convert a `float` to a `_Float16`, or even initialize a `_Float16`? (And/or print with printf?)
I'm developing a library which uses _Float16s for many of the constants to save space when passing them around. However, just testing, it seems that telling GCC to just "set it to 1" isn't ...
1
vote
2
answers
175
views
How to force gcc to do printf checks on non-literal format strings?
const char* const non_literal_string = "Hello %d";
void my_print()
{
/*
* I would like GCC to throw a warning when compiling this line because the
* argument is not of int ...
- 362
0
votes
1
answer
90
views
printf() prints only the first character
Recently I came across an example from the book "The C Programming Language" and decided to run it:
#include <stdio.h>
#define IN 1
#define OUT 0
int main() {
int c, nl, nw, nc, ...
- 15
3
votes
2
answers
91
views
How to leverage the [*]printf format type specification warnings?
As we all know and love (or hate), GCC has the capability of issuing warnings when you attempt to use the printf() family of functions with mismatched type specifications. In our code, we have a ...
- 580
0
votes
1
answer
227
views
Why C is fine with overwriting memory sometimes? Fatal glibc error: malloc assertion failure in sysmalloc
Why code A works fine, but code B gives an error?
The only difference is a printf. Also note that I'm accessing out of range memory.
And GCC is fine with that. I even overwritten RAM memory easily in ...
- 27
0
votes
3
answers
162
views
Using the malloc function once initializes all uninitialized variables with a 0
The malloc function is not supposed to initialize any value to any variable it is used on, like the calloc function does. Why then do I keep getting the initialized value of even other varibales to ...
user25659167
1
vote
1
answer
152
views
c language, When decimal digit of %g in printf equal to 0.5, and length is more than 6, it is not upper ceil, why?
Here is my program:
#include <stdio.h>
int main()
{
printf("%g\n", 100000.5);
printf("%g\n", 100001.5);
printf("%g\n", 100002.5);
printf("%g\n&...
- 127
0
votes
2
answers
104
views
Printing doubles with large precision with printf, compiling with GCC
When printing with printf in a C program and specify how much characters I want after the decimal point with %.20f, it only gives me 15 characters and the rest are 0. I compile with GCC with the ...
0
votes
1
answer
99
views
Custom printf function segmentation fault
can anyone help with this project task?
I am to build a custom printf funcion after my C classes.
I'm restricted to use most standard C functions.
Must follow Aunty Betty coding style and below is the ...
- 15
0
votes
0
answers
463
views
Can't see the printf() output while debugging in VS Code
I tried running the following C program:
#include <stdio.h>
main()
{
for (int fehr = 0; fehr < 300; fehr = fehr + 20)
{
printf("%3d\t%6f\n", fehr, (5.0 / 9.0) * (fehr ...
-3
votes
1
answer
3k
views
Breaking down %5d%*.*f format specifier in C for precise output formatting
I'm working with formatted output in C and encountered the format string %5d%*.*f. While I understand the basic use of %d for integers and %f for floating-point numbers, I'm specifically seeking ...
- 13
0
votes
1
answer
113
views
GCC : left shift operator on unsigned long long int does not work when shift is greater than 32?
Considering this simple example :
unsigned long long int my_int=0b10100110;
printf("%.64B\n",my_int<<40);
Why is the output zero ? unsigned long long int is used (sizeof = 8), 64 bits ...
- 2,461
0
votes
1
answer
86
views
Correct use of param-no in GNU C's printf format specification
I am working on a helper function using printf format strings, so I started to examine printf format specifications in more detail, and found that GNU's manual allows the use of a param-no: https://...
- 3,817
1
vote
0
answers
2k
views
How to disable the Debugging Console of Raylib, without disabling also the other outputs?
Sometimes I want to print the value of a variable (or something else) in the console with printf. The problem is that, when compiling the C-Programm with GCC and adding the flags "-Wl,--subsystem,...
- 92
0
votes
1
answer
380
views
Machine-independent printf() of int64_t? [duplicate]
Consider the following snippet, compiled with gcc -Wall for two different architectures:
int64_t x;
printf("A: %ld\n", x);
printf("B: %lld\n", x);
When compiling for a 32 bit ...
- 35.3k