New compiler method: check_header

This checks not only for existence, but also for usability of the
header, which means it does a full compilation and not just
pre-processing or __has_include.

Fixes https://github.com/mesonbuild/meson/issues/2246

3 files changed, 35 insertions, 0 deletions

diff --git a/mesonbuild/compilers/c.py b/mesonbuild/compilers/c.py
index 13b3dcc..4cc9660 100644
--- a/mesonbuild/compilers/c.py
+++ b/mesonbuild/compilers/c.py
@@ -266,6 +266,12 @@ class CCompiler(Compiler):
         code = 'int main(int argc, char **argv) { int class=0; return class; }\n'
         return self.sanity_check_impl(work_dir, environment, 'sanitycheckc.c', code)
 
+    def check_header(self, hname, prefix, env, extra_args=None, dependencies=None):
+        fargs = {'prefix': prefix, 'header': hname}
+        code = '''{prefix}
+        #include <{header}>'''
+        return self.compiles(code.format(**fargs), env, extra_args, dependencies)
+
     def has_header(self, hname, prefix, env, extra_args=None, dependencies=None):
         fargs = {'prefix': prefix, 'header': hname}
         code = '''{prefix}
diff --git a/mesonbuild/compilers/compilers.py b/mesonbuild/compilers/compilers.py
index 56a0ab2..c5f7df3 100644
--- a/mesonbuild/compilers/compilers.py
+++ b/mesonbuild/compilers/compilers.py
@@ -710,6 +710,9 @@ class Compiler:
     def get_option_link_args(self, options):
         return []
 
+    def check_header(self, *args, **kwargs):
+        raise EnvironmentException('Language %s does not support header checks.' % self.get_display_language())
+
     def has_header(self, *args, **kwargs):
         raise EnvironmentException('Language %s does not support header checks.' % self.get_display_language())
 
diff --git a/mesonbuild/interpreter.py b/mesonbuild/interpreter.py
index c574479..4f2d45e 100644
--- a/mesonbuild/interpreter.py
+++ b/mesonbuild/interpreter.py
@@ -843,6 +843,7 @@ class CompilerHolder(InterpreterObject):
                              'compute_int': self.compute_int_method,
                              'sizeof': self.sizeof_method,
                              'get_define': self.get_define_method,
+                             'check_header': self.check_header_method,
                              'has_header': self.has_header_method,
                              'has_header_symbol': self.has_header_symbol_method,
                              'run': self.run_method,
@@ -1236,6 +1237,31 @@ class CompilerHolder(InterpreterObject):
         'args',
         'dependencies',
     })
+    def check_header_method(self, args, kwargs):
+        if len(args) != 1:
+            raise InterpreterException('check_header method takes exactly one argument.')
+        check_stringlist(args)
+        hname = args[0]
+        prefix = kwargs.get('prefix', '')
+        if not isinstance(prefix, str):
+            raise InterpreterException('Prefix argument of has_header must be a string.')
+        extra_args = self.determine_args(kwargs)
+        deps = self.determine_dependencies(kwargs)
+        haz = self.compiler.check_header(hname, prefix, self.environment, extra_args, deps)
+        if haz:
+            h = mlog.green('YES')
+        else:
+            h = mlog.red('NO')
+        mlog.log('Check usable header "%s":' % hname, h)
+        return haz
+
+    @permittedKwargs({
+        'prefix',
+        'no_builtin_args',
+        'include_directories',
+        'args',
+        'dependencies',
+    })
     def has_header_method(self, args, kwargs):
         if len(args) != 1:
             raise InterpreterException('has_header method takes exactly one argument.')