C99 (C9X during its development, formally ISO/IEC 9899:1999) is a past version of the C programming language open standard. It extends the previous version (C90) with new features for the language and the standard library, and helps implementations make better use of available computer hardware, such as IEEE 754-1985 floating-point arithmetic, and compiler technology. The C11 version of the C programming language standard, published in 2011, updates C99.
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👉 C99 in the context of OpenCL
OpenCL (Open Computing Language) is a framework for writing programs that execute across heterogeneous platforms consisting of central processing units (CPUs), graphics processing units (GPUs), digital signal processors (DSPs), field-programmable gate arrays (FPGAs) and other processors or hardware accelerators. OpenCL specifies a programming language (based on C99) for programming these devices and application programming interfaces (APIs) to control the platform and execute programs on the compute devices. OpenCL provides a standard interface for parallel computing using task- and data-based parallelism.
OpenCL is an open standard maintained by the Khronos Group, a non-profit, open standards organisation. Conformant implementations (passed the Conformance Test Suite) are available from a range of companies including AMD, Arm, Cadence, Google, Imagination, Intel, Nvidia, Qualcomm, Samsung, SPI and Verisilicon.
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C99 in the context of CompCert
CompCert is a formally verified optimizing compiler for a large subset of the C99 programming language (known as Clight) which currently targets PowerPC, ARM, RISC-V, x86 and x86-64 architectures. This project, led by Xavier Leroy, started officially in 2005, funded by the French institutes ANR and INRIA. The compiler is specified, programmed and proven in the Rocq proof assistant. It aims to be used for programming embedded systems requiring reliability. The performance of its generated code is often close to that of GCC (version 3) at optimization level -O1, and always better than that of GCC without optimizations.
Since 2015, AbsInt offers commercial licenses, provides support and maintenance, and contributes to the advancement of the tool. CompCert is released under a noncommercial license, and is therefore not free software, although some of its source files are dual-licensed with the GNU Lesser General Public License version 2.1 or later or are available under the terms of other licenses.
View the full Wikipedia page for CompCert