Questions tagged [gcc]
For code written to be compiled specifically by the GCC, which stands for the GNU Compiler Collection. Developers often compile several languages using this compiler collection.
23
questions
12
votes
3
answers
1k
views
Register "%b" conversion specifier
I'm writing a library to register the b, B conversion specifiers and make them work the closest possible to ...
11
votes
1
answer
1k
views
Computing average without overflows and with half-decent precision
At some point I needed to compute the average of a big collection of integers. I knew the size of the collection prior computation, but a naive average computation was prone to integer overflow while ...
- 20k
10
votes
3
answers
5k
views
C++ Template to implement the Factory Pattern
Design
A template class that will create a concrete instance of an interface class when given the name (as a string) of the concrete class.
This design is often seen in code, so the purpose of this ...
- 383
10
votes
1
answer
668
views
Vectorizing the product of an array of complex numbers
I am trying to write fast/optimal code to vectorize the product of an array of complex numbers. In simple C this would be:
...
- 191
7
votes
2
answers
622
views
Consolidating GNU C's and C23's attributes
C23 has introduced attribute specifier sequences. Consequently, the header below attempts to conditionally define macros for these sequences (for my own use cases). In cases where a compiler does not ...
- 5,669
6
votes
3
answers
549
views
4 different implementations of modulo with fully defined behavior
I've implemented the 3 variants of the modulo operation described on this Wikipedia page.
The goal is to have fully defined behavior for all inputs.
Code
Implementation with truncated division (result ...
- 163
6
votes
2
answers
4k
views
128-bit integer type in GCC/Clang
When working on my projects, I often need a 128-bit integer type. For this purpose, I use the __int128 compiler extension. Here is the implementation I am currently ...
- 309
6
votes
2
answers
1k
views
Bash script - compile and run c++ code for coding competitions
This is a simple bash script that I use to compile and run single C++ files for coding competitions.
Features:
Detects if there is a corresponding .in file next to ...
- 165
5
votes
3
answers
983
views
Encapsulating snprintf to avoid repetition of sizeof
Correct usage of snprintf involves very long and repetitive lines:
...
4
votes
1
answer
1k
views
Macro for counting number of elements in an array
We all know the classic version of counting the number of elements in a C array: sizeof(a)/sizeof(*a)
But this is dangerous, because if used on a pointer it will ...
- 903
4
votes
1
answer
161
views
32x32x32 units octree, that supports 15-bit data units
The idea is to have an octree that stores a 32x32x32 region of 15 bit values more efficiently than a 32x32x32 array, because if all 8 leaf nodes of a given branch are the same, the branch does not ...
- 928
4
votes
3
answers
376
views
Encapsulating snprintf to simplify usage: sbprintf & swnprintf
After writing swnprintfand sbprintf in C (Encapsulating snprintf to avoid repetition of sizeof), I've written a C++ version of ...
3
votes
2
answers
392
views
A little C++ program to have timed rounds for a game
I know it could be better, but I’m new to C++, so I don’t know many of the tricks, along with some of the includes that are already obsolete.
This program asks for names as input, adds a time for ...
- 31
3
votes
3
answers
951
views
Efficiently read a file into a (C) string using POSIX APIs
Exactly what the title says, this is a C++ class that attempts to read a file into a null-terminated string as efficiently as possible, using POSIX APIs. Obviously this is not intended to be portable ...
- 258
3
votes
2
answers
272
views
Reference-counted smart pointer in C
About
I've been experimenting with gcc's __cleanup__ attribute, and thought it'd be a great fit for a memory-safe smart pointer for C.
This is the implementation. ...
- 107
3
votes
1
answer
137
views
Clang preprocessor concatenates an extra space vs. gcc - standard C99
I maintain a C library project both on gcc and clang.
I am looking for advice on how to make the following macros more portable, terse, readable or standard abiding.
When I compile
...
- 211
3
votes
2
answers
965
views
Makefile for a small JNI project
So I'm going to publish this small project on GitHub and I thought I'd better do a makefile for it. The source code consists of
1 Java Class
1 Native JNI module written in C
1 stdlib wrapper object ...
- 193
3
votes
0
answers
664
views
Generic Makefile for C projects
I'm trying to create a generic Makefile that will work with the following directory structure:
Project Directory
Makefile
main.c source file
source directory
Source files
include directory
Header ...
- 351
2
votes
1
answer
457
views
Printing 64-bit decimal numbers in freestanding environment
I need to print signed 64-bit numbers in decimal form. Program runs in freestanding environment (no C library available, libgcc may be unavailable too, or may not work correctly). So I can't use ...
- 159
2
votes
0
answers
75
views
String to long double conversion using FBLD
I always wanted to try fbld x87 instruction to aid to convert string to floating point value.
I sure a chance to face this instruction in disassembly of all the ...
- 624
0
votes
3
answers
120
views
Safer & simpler allocation functions and macros
I wrote a bunch of functions and macros for safer and simpler allocation. They are documented in their files.
Disclaimer:
The library requires POSIX extensions, GCC extensions, and LIBBSD ...
0
votes
1
answer
108
views
gcc constant time implemenation [closed]
I need to make the following function time constant - I have already removed if statements and have written it down to one line in the loop.
...
- 103
-7
votes
1
answer
130
views
Can you please give feedback on my C++ Code? [closed]
Can you please give feedback on my C++ code so I can get better at writing code? I want a code that is well written.
This Code uses the cstdio include for good performance and cstdint include because ...
