| Original author(s) | Roland McGrath |
|---|---|
| Developer(s) | GNU Project, most contributions by Ulrich Drepper |
| Initial release | 1987; 38 years ago (1987)[1] |
| Stable release | 2.41[2]  / 29 January 2025 |
| Repository | |
| Written in | C |
| Operating system | Unix-like |
| Type | Runtime library |
| License | 2001:LGPL-2.1-or-later[a] 1992:LGPL-2.0-or-later[b] |
| Website | www |
TheGNU C Library, commonly known asglibc, is theGNU Project implementation of theC standard library. It provides a wrapper around the system calls of theLinux kernel and other kernels for application use. Despite its name, it now also directly supportsC++ (and, indirectly, otherprogramming languages). It was started in the 1980s by theFree Software Foundation (FSF) for theGNU operating system.
glibc isfree software released under theGNU Lesser General Public License.[3] The GNU C Library project provides the core libraries for the GNU system, as well as many systems that useLinux as thekernel. These libraries provide criticalAPIs includingISOC11,POSIX.1-2008,BSD, OS-specific APIs and more. These APIs include such foundational facilities asopen,read,write,malloc,printf,getaddrinfo,dlopen,pthread_create,crypt,login,exit and more.
| Version | Date | Highlights |
|---|---|---|
| 0.1 – 0.6 | October 1991 – February 1992 | |
| 1.0 | February 1992 | |
| 1.01 – 1.09.3 | March 1992 – December 1994 | |
| 1.90 – 1.102 | May 1996 – January 1997 | |
| 2.0 | January 1997 | |
| 2.0.1 | January 1997 | |
| 2.0.2 | February 1997 | |
| 2.0.91 | December 1997 | |
| 2.0.95 | July 1998 | |
| 2.1 | February 1999 | |
| 2.1.1 | March 1999 | |
| 2.2 | November 2000 | |
| 2.2.1 | January 2001 | |
| 2.2.2 | February 2001 | |
| 2.2.3 | March 2001 | |
| 2.2.4 | July 2001 | |
| 2.3 | October 2002 | |
| 2.3.1 | October 2002 | |
| 2.3.2 | February 2003 | |
| 2.3.3 | December 2003 | |
| 2.3.4 | December 2004 | Minimum forLinux Standard Base (LSB) 3.0 |
| 2.3.5 | April 2005 | |
| 2.3.6 | November 2005 | |
| 2.4 | March 2006 | Minimum forLSB 4.0, initialinotify support |
| 2.5 | September 2006 | Fullinotify support.RHEL5 end of support was November 30, 2020; 4 years ago (2020-11-30) |
| 2.6 | May 2007 | |
| 2.7 | October 2007 | |
| 2.8 | April 2008 | |
| 2.9 | November 2008 | |
| 2.10 | May 2009 | Minimum forLSB 5.0. InitialpsiginfoArchived 19 September 2021 at theWayback Machine support. |
| 2.11 | October 2009 | SLES11 reached end of long-term support inMarch 2022. |
| 2.12 | May 2010 | |
| 2.13 | January 2011 | |
| 2.14 | June 2011 | |
| 2.15 | March 2012 | |
| 2.16 | June 2012 | x32 ABI support,ISO C11 compliance,SystemTap |
| 2.17 | December 2012 | 64-bit ARM support |
| 2.18 | August 2013 | ImprovedC++11 support. Support for IntelTSX lock elision. Support for the XilinxMicroBlaze and IBMPOWER8 microarchitectures. |
| 2.19 | February 2014 | SystemTap probes formalloc. GNU Indirect Function (IFUNC) support for ppc32 and ppc64. New feature test macro _DEFAULT_SOURCE to replace _SVID_SOURCE and _BSD_SOURCE. Preliminary safety documentation for all functions in the manual. ABI change in ucontext and jmp_buf for s390/s390x. |
| 2.20 | September 2014 | Support for file description locks |
| 2.21 | February 2015 | New semaphore implementation |
| 2.22 | August 2015 | Support to enableGoogle Native Client (NaCl), that originally ran on x86, running onARMv7-A,Unicode 7.0 |
| 2.23 | February 2016 | Unicode 8.0 |
| 2.24 | August 2016 | Some deprecated features have been removed |
| 2.25 | February 2017 | Thegetentropy andgetrandom functions, and the<sys/random.h> header file have been added. |
| 2.26 | August 2017 | Improved performance (per-thread cache for malloc), Unicode 10 support |
| 2.27 | February 2018 | Performance optimizations.RISC-V support. |
| 2.28 | August 2018 | statx,renameat2, Unicode 11.0.0 |
| 2.29 | February 2019 |
|
| 2.30 | August 2019 | Unicode 12.1.0, the dynamic linker accepts the--preload argument to preload shared objects, thegettid function has been added on Linux, Minguo (Republic of China) calendar support, new Japanese era added to ja_JP locale, memory allocation functions fail with total object size larger thanPTRDIFF_MAX;CVE-2019-7309 and CVE-2019-9169 fixed[8] |
| 2.31 | February 2020 | InitialC23 standard support |
| 2.32 | August 2020 | Unicode 13.0, 'access' attribute for better warnings in GCC 10, i.e. to "help detect buffer overflows and other out-of-bounds accesses"[9] |
| 2.33 | February 2021 | HWCAPS |
| 2.34 | August 2021 | libpthread, libdl, libutil, libanl has been integrated into libc. |
| 2.35 | February 2022 | Unicode 14.0, C.UTF-8 locale, restartable sequences. RemovedIntel MPX support. |
| 2.36 | August 2022 | |
| 2.37 | February 2023 | |
| 2.38 | August 2023 | The strlcpy and strlcat functions added. libmvec support for ARM64. |
| 2.39 | January 2024 | The stdbit.h header has been added from ISO C2X. Support for shadow stacks on x86_64, new security features, and the removal of libcrypt. |
| 2.40 | July 2024 | Partial support for the ISOC23 standard, a new tunable for the testing ofsetuid programs, improved 64-bit ARM vector support. |
| 2.41 | January 2025 | Addsinpi,cospi,tanpi functions. |
The glibc project was initially written mostly by Roland McGrath, working for theFree Software Foundation (FSF) in the summer of 1987 as a teenager.[10][11] In February 1988, FSF described glibc as having nearly completed the functionality required byANSI C.[12] By 1992, it had the ANSI C-1989 and POSIX.1-1990 functions implemented and work was under way on POSIX.2.[13] In September 1995 Ulrich Drepper made his first contribution to the glibc and by 1997 most commits were made by him. Drepper held the maintainership position for many years and until 2012 accumulated 63% of all commits to the project.[14]
In May 2009 glibc was migrated to aGit repository.[14]
In 2010, a licensing issue was resolved which was caused by theSun RPC implementation in glibc that was not GPLcompatible. It was fixed by re-licensing the Sun RPC components under theBSD license.[15][16]
In 2014, glibc suffered from an ABI breakage bug on s390.[17]
In July 2017, 30 years after he started glibc, Roland McGrath announced his departure, "declaring myself maintainer emeritus and withdrawing from direct involvement in the project. These past several months, if not the last few years, have proven that you don't need me anymore".[10]
In 2018, maintainer Raymond Nicholson removed a joke aboutabortion from the glibc source code. It was restored later by Alexandre Oliva afterRichard Stallman demanded to have it returned.[18]
In 2021, thecopyright assignment requirement to theFree Software Foundation was removed from the project.[19]
In 1994, the developers of theLinux kernelforked glibc. Their fork, "Linux libc", was maintained separately until around 1998. Because the copyright attribution was insufficient, changes could not be merged back to the GNU Libc.[20] When the FSF released glibc 2.0 in January 1997, the kernel developers discontinued Linux libc due to glibc 2.0's superior compliance with POSIX standards.[21] glibc 2.0 also had betterinternationalisation and more in-depth translation,IPv6 capability, 64-bit data access, facilities for multithreaded applications, future version compatibility, and the code was more portable.[22] The last-used version of Linux libc used the internal name (soname)libc.so.5. Following on from this, glibc 2.x on Linux uses the sonamelibc.so.6[23][better source needed]
In 2009,Debian and a number ofderivatives switched from glibc to the variant[25] eglibc.[26] Eglibc was supported by aconsortium consisting ofFreescale,MIPS,MontaVista andWind River.[27] It contained changes that made it more suitable forembedded usage and had added support for architectures that were not supported by glibc, such as thePowerPC e500. The code of eglibc was merged back into glibc at version 2.20.[28] Since 2014, eglibc is discontinued. TheYocto Project and Debian also moved back to glibc since the release ofDebian Jessie.[29]
Starting in 2001 the library's development had been overseen by a committee,[30] with Ulrich Drepper[31] kept as the lead contributor and maintainer. Thesteering committee installation was surrounded by a public controversy, as it was openly described by Ulrich Drepper as a failedhostile takeover maneuver byRichard Stallman.[32][33][34][35]
In March 2012, the steering committee voted to disband itself and remove Drepper in favor of a community-driven development process, with Ryan Arnold, Maxim Kuvyrkov, Joseph Myers, Carlos O'Donell, and Alexandre Oliva holding the responsibility of GNU maintainership (but no extra decision-making power).[36][37][38]
glibc provides the functionality required by theSingle UNIX Specification,POSIX (1c, 1d, and 1j) and some of the functionality required byISOC11,ISOC99,Berkeley Unix (BSD) interfaces, theSystem V Interface Definition (SVID) and theX/Open Portability Guide (XPG), Issue 4.2, with all extensions common to XSI (X/Open System Interface) compliant systems along with all X/Open UNIX extensions.
In addition, glibc also provides extensions that have been deemed useful or necessary while developingGNU.
glibc is used in systems that run many differentkernels and differenthardware architectures. Its most common use is in systems using theLinux kernel onx86 hardware, however, officially supported hardware[39] includes:ARM,ARC,C-SKY,DEC Alpha,IA-64,Motorola m68k,MicroBlaze,MIPS,Nios II,PA-RISC,PowerPC,RISC-V,s390,SPARC, andx86 (old versions supportTILE). It officially supports theHurd andLinux kernels. Additionally, there are heavily patched versions that run on the kernels ofFreeBSD andNetBSD (from whichDebian GNU/kFreeBSD andDebian GNU/NetBSD systems are built, respectively), as well as a forked-version ofOpenSolaris.[40] It is also used (in an edited form) and namedlibroot.so inBeOS andHaiku.[41]
glibc has been criticized as being "bloated" and slower than other libraries in the past, e.g. byLinus Torvalds[42] andembedded Linux programmers. For this reason, severalalternative C standard libraries have been created which emphasize a smaller footprint. However, many small-device projects use GNU libc over the smaller alternatives because of its application support, standards compliance, and completeness. Examples includeOpenmoko[43] andFamiliar Linux for iPaq handhelds (when using theGPE display software).[44]
glibc does not implement bounds-checking interfaces defined inC11 and did not implement strlcpy and strlcat[45][46] until 2023 on the grounds that "in practice these functions can cause trouble, as their intended use encourages silent data truncation, adds complexity and inefficiency, and does not prevent all buffer overruns in the destinations."[47] The FAQ pointed out that the bounds-checking interfaces were optional in the ISO standard and that snprintf was available as an alternative.[47]
There arecompatibility layers ("shims") to allow programs written for other ecosystems to run on glibc interface offering systems. These includelibhybris, a compatibility layer forAndroid'sBionic, andWine, which can be seen as a compatibility layer fromWindows APIs to glibc and other native APIs available on Unix-like systems.
LGPL-2.1-or-later in the headers
LGPL-2.1-or-later in the headers
LGPL-2.0-or-later in the headers
Most libraries are done. Roland McGrath [...] has a nearly complete set of ANSI C library functions. We hope they will be ready some time this spring.
It now contains all of the ANSI C-1989 and POSIX.1-1990 functions, and work is in progress on POSIX.2 and Unix functions (BSD and System V)
Of the nearly 19,000 commits found in the project's git repository (which contains changes back to 1995), over 12,000 were made by Ulrich.
the split between GNU LIBC and the Linux LIBC -- it went on for years while Linux stabilized, and then the forks re-merged into one project
{{cite book}}: CS1 maint: location missing publisher (link){{cite book}}: CS1 maint: location missing publisher (link)In 2001 The GNU C Library Steering Committee ..., was formed and currently consists of Mark Brown, Paul Eggert, Andreas Jaeger, Jakub Jelinek, Roland McGrath and Andreas Schwab.
A few weeks ago RMS started the next attack on me (a single mail, followed by indirect tries to take influence, followed by another mail today). The essence is that he complains I am not following "GNU policies" and therefore have to be replaced by a steering committee of which I could be a part. Some of you (namely Roland and Andreas S.) probably know about this since he proposed both as other members of the committee. In addition there was Mark Brown listed (I know somebody of this name at IBM who would also fit in this group but I'm not sure whether it is really him.) Anyhow, I completely reject this. It is not helping at all, the opposite is true. First, I am not aware of any essential policies I'm violating. The only ones are that I'm not following orders from RMS which clearly have political intends (which is of course a sacrilege) and possibly that I do not care about Winblowz (if the latter counts at all). None of this will change in any way.
And now for some not so nice things. Stallman recently tried what I would call a hostile takeover of the glibc development. He tried to conspire behind my back and persuade the other main developers to take control so that in the end he is in control and can dictate whatever pleases him. This attempt failed but he kept on pressuring people everywhere and it got really ugly. In the end I agreed to the creation of a so-called "steering committee" (SC).
libroot.so is not part of GNU project and is included in Haiku source code.
We will use glibc (not uClibC) ... The alternatives may save more space and be more optimized, but are more likely to give us integration headaches
Question: which version of the GLIBC was used to build the Familiar 0.8.4 ? Answer: 2.3.3
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