While the standard itself is not complete yet, compilers are already adding support for the known parts of the new standard. Many compilers vendors and C programmers moved to ISO C11 rather quickly.

C11: The latest standard is the 2011 ISO standard.

The move from C89 to C99 was initially slow, with the ISO C99 standard slowly gaining ground over the years.

C99: The 1999 ISO standard introduced major new features.

It never became popular, with most users moving directly from C89/C90 to C99.

C95: In 1995, some minor new features were introduced, resulting in what is commonly called the ISO C95 standard.

This standard is usually referred to as ANSI C89 or ISO C90.

C89: C was first standardized by ANSI in 1989, which (with minor fixes) became an ISO standard in 1990.

The input language to be accepted by C compilers is defined by international standards, with the ANSI C89/ISO C90, ISO C99 and ISO C11 being the most important. 'SDCC for ST7, STM8' is an unmaintained fork of an old SDCC version. 'ST8CC' seems rather incomplete and does not run under current operating systems. Neither has been included in the comparison. There are two more: 'ST8CC' and 'SDCC for ST7, STM8'.

IAR: The comparison uses the time-limited IAR 3.11.1.207 Embedded Workbench for STMicroelectronics STM8, which is the current version as of end of February 2020.

Raisonance: RCSTM8 COMPILER 2.62.17.263, which is the current version as of end of February 2020.

SDCC: SDCC 4.0.0 from the end of January 2020.

Cosmic: The comparison uses the STM8 Free Special Edition 4.4.11, the current version as of end of February 2020.

There are currently multiple C implementations targeting the STM8: There is also a similar comparison from 2018, and a summary of the changes from mid-2016 to early 2018 and to early 2020. The author is a SDCC user and developer, but tried to do an objective comparison here.

This is a comparison of currently (early 2020) available C implementations targeting the STM8.

Raisonance free c compiler for st8