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| -rw-r--r-- | docs/markdown/Compiler-properties.md | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/docs/markdown/Compiler-properties.md b/docs/markdown/Compiler-properties.md index 579417a..1228f42 100644 --- a/docs/markdown/Compiler-properties.md +++ b/docs/markdown/Compiler-properties.md @@ -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? == |