If I may add my two cents...
I highly recommend reading through the standard library and then looking at how they are implemented in actual C. The string library is probably the most important, this is where most people mess up!
If you can figure out pointers and how to actually get the size of things (sizeof(*char) doesn't get you the size of what it is pointing at... it gets you the size of a pointer which varies depending on the architecture. sizeof(myArray) doesn't give you the number of elements in an array, it gives you the number of bytes your array can hold, to get the number of elements you must do sizeof(myarray)/sizeof(myarray[0]). sizeof() is a compile-time operator, it knows nothing of runtime) you will be pretty much 99% of the way there.
https://en.cppreference.com/w/c/string/byte
https://github.com/lattera/glibc/tree/maste
lattera
glibc
C2015–2026
lattera / glibc · Archived
glibc
GNU Libc - Extremely old repo used for research purposes years ago. Please do not rely on this repo.
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If I may add my two cents... I highly recommend reading through the standard library and then looking at how they are implemented in actual C. The string library is probably…
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| 2015 | 2015-01-01 00:00:00 UTC | 2016-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2016 | 2016-01-01 00:00:00 UTC | 2017-01-01 00:00:00 UTC | 3 | 0 | 3 |
| 2017 | 2017-01-01 00:00:00 UTC | 2018-01-01 00:00:00 UTC | 5 | 0 | 5 |
| 2018 | 2018-01-01 00:00:00 UTC | 2019-01-01 00:00:00 UTC | 2 | 0 | 2 |
| 2019 | 2019-01-01 00:00:00 UTC | 2020-01-01 00:00:00 UTC | 2 | 0 | 2 |
| 2020 | 2020-01-01 00:00:00 UTC | 2021-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2021 | 2021-01-01 00:00:00 UTC | 2022-01-01 00:00:00 UTC | 4 | 0 | 4 |
| 2022 | 2022-01-01 00:00:00 UTC | 2023-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2023 | 2023-01-01 00:00:00 UTC | 2024-01-01 00:00:00 UTC | 4 | 1 | 3 |
| 2024 | 2024-01-01 00:00:00 UTC | 2025-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2025 | 2025-01-01 00:00:00 UTC | 2026-01-01 00:00:00 UTC | 2 | 0 | 2 |
| 2026 (partial) | 2026-01-01 00:00:00 UTC | 2027-01-01 00:00:00 UTC | 1 | 0 | 1 |
From the project README
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This directory contains the sources of the GNU C Library.
See the file "version.h" for what release version you have.
The GNU C Library is the standard system C library for all GNU systems,
and is an important part of what makes up a GNU system. It provides the
system API for all programs written in C and C-compatible languages such
as C++ and Objective C; the runtime facilities of other programming
languages use the C library to access the underlying operating system.
In GNU/Linux systems, the C library works with the Linux kernel to
implement the operating system behavior seen by user applications.
In GNU/Hurd systems, it works with a microkernel and Hurd servers.
The GNU C Library implements much of the POSIX.1 functionality in the
GNU/Hurd system, using configurations i[4567]86-*-gnu.
When working with Linux kernels, this version of the GNU C Library
requires Linux kernel version 3.2 or later.
Also note that the shared version of the libgcc_s library must be
installed for the pthread library to work correctly.
The GNU C Library supports these configurations for using Linux kernels:
aarch64*-*-linux-gnu
alpha*-*-linux-gnu
arm-*-linux-gnueabi
hppa-*-linux-gnu
i[4567]86-*-linux-gnu
x86_64-*-linux-gnu Can build either x86_64 or x32
ia64-*-linux-gnu
m68k-*-linux-gnu
microblaze*-*-linux-gnu
mips-*-linux-gnu
mips64-*-linux-gnu
powerpc-*-linux-gnu Hardware or software floating point, BE only.
powerpc64*-*-linux-gnu Big-endian and little-endian.
s390-*-linux-gnu
s390x-*-linux-gnu
riscv64-*-linux-gnu
sh[34]-*-linux-gnu
sparc*-*-linux-gnu
sparc64*-*-linux-gnu
If you are interested in doing a port, please contact the glibc
maintainers; see http://www.gnu.org/software/libc/ for more
information.
See the file INSTALL to find out how to configure, build, and install
the GNU C Library. You might also consider reading the WWW pages for
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The GNU C Library is (almost) completely documented by the Texinfo manual
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and contains some known errors and omissions; we regret that we do not
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Read the full README on GitHubWhat Hacker News says
2 sourcesIn An Introduction to C and GUI Programming
I cannot tell you if it is the solution they chose, but the fastest known implementation for single-precision FMA using double-precision multiplication and addition on conventional hardware is to use “round-to-odd” for the intermediate result. Any libc implementing “fmaf” for an architecture that doesn't have it has the same problem, and the solution looks like:
https://github.com/lattera/glibc/blob/b4d5b8b02133e0c317e6c8...
“round-to-odd” is not a standardized rounding mode, even though it is so useful that some argue it should be. It can be emulated by the following sequence:
/* Reset rounding mode and test for inexact simultaneously. */
int j = libc_feupdateenv_test (&env, FE_INEXACT) != 0;
if ((u.ieee.mantissa1 & 1) == 0 && u.ieee.exponent != 0x7ff)
u.ieee.mantissa1 |= j;
The sequence has the drawback of not pipel
Read the rest
ining well on modern processors, but it's still faster than any known alternative, and at least the code is short.