Virtualization
/
meson
mirror of https://gitlab.com/qemu-project/meson.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

Docs: Mention important macOS caveat about function detection [ci skip]

This commit is contained in:
Marvin Scholz 2018-04-15 22:34:36 +02:00 committed by Nirbheek Chauhan
parent ef81a013a5
commit eadaf92794
1 changed files with 18 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
docs/markdown/Compiler-properties.md
View File

@ -160,15 +160,30 @@ Does a function exist?
Just having a header doesn't say anything about its
contents. Sometimes you need to explicitly check if some function
exists. This is how we would check whether the function `somefunc`
exists in header `someheader.h`
exists. This is how we would check whether the function `open_memstream`
exists in header `stdio.h`
```meson
if compiler.has_function('somefunc', prefix : '#include<someheader.h>')
if compiler.has_function('open_memstream', prefix : '#include <stdio.h>')
# function exists, do whatever is required.
endif
```
Note that, on macOS programs can be compiled targeting older macOS
versions than the one that the program is compiled on. It can't be
assumed that the OS version that is compiled on matches the OS
version that the binary will run on.
Therefore when detecting function availability with `has_function`, it
is important to specify the correct header in the prefix argument.
In the example above, the function `open_memstream` is detected, which
was introduced in macOS 10.13. When the user builds on macOS 10.13, but
targeting macOS 10.11 (`-mmacosx-version-min=10.11`), this will correctly
report the function as missing. Without the header however, it would lack
the necessary availability information and incorrectly report the function
as available.
Does a structure contain a member?
==