Re: Why does stdio.h have to be included before readline/readline.h (installed via homebrew) on macOS?

[Chet Ramey]

On 5/19/21 1:11 PM, Peng Yu wrote:
> But on Linux, stdio.h is not needed. Can't the behavior be made the
> same on Linux and macOS?

If you would like Apple to change its header files so that you don't need
stdio.h for stdio definitions, or string.h for strcmp(), file a bug report
with Apple.

Or you could include <stdio.h> as the readline documentation recommends
(and string.h for the strcmp prototype).

Historically, stdio.h is where you found definitions for NULL and EOF. If
you wanted to write something like

while ((line = readline ("prompt> ")) != NULL)

as many programs do -- including yours -- you needed it.

In your case, it doesn't matter whether or not your program includes 
stdio.h on macOS. It doesn't compile because it doesn't include string.h,
using

$ clang --version
Apple clang version 12.0.0 (clang-1200.0.32.29)
Target: x86_64-apple-darwin19.6.0
Thread model: posix
InstalledDir: 
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin


--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/