3BSD was released at the end of 1979 according to wikipedia, and that's just the oldest BSD source I could find, so it may have been in even older versions.
Before ANSI/ISO C I don't think there was really a "math.h" to look for - as it may be different on different systems, but as so many things derive from BSD I wouldn't be surprised if it was "de-facto" standardised to what that supported.
Comments
Table 8-3, page 8-7 (pdf page 97):
http://www.bitsavers.org/www.computer.museum.uq.edu.au/pdf/D...
1965: https://www.ecma-international.org/publications-and-standard... pdf page 36
Nice find. Anyone have a way to search for old versions "math.h"? The 1989 version of ANSI C had atan2:
https://web.archive.org/web/20161223125339/http://flash-gord...
...but I wonder when it first hit the scene.
According to https://unix.superglobalmegacorp.com/ it was in 3bsd libm -https://unix.superglobalmegacorp.com/cgi-bin/cvsweb.cgi/3BSD...
3BSD was released at the end of 1979 according to wikipedia, and that's just the oldest BSD source I could find, so it may have been in even older versions.
Before ANSI/ISO C I don't think there was really a "math.h" to look for - as it may be different on different systems, but as so many things derive from BSD I wouldn't be surprised if it was "de-facto" standardised to what that supported.