Syntax errors while parsing Linux header files #82
Description
On Debian Stretch, ctypesgen (1.0.2) produces syntax errors during the parsing phase, when trying to generate a ctype wrapper for headers assert.h or sys/cdefs.h (or any header file that includes one of them).
$ ctypesgen /usr/include/assert.h > /dev/null
WARNING: No libraries specified
INFO: Status: Preprocessing /tmp/tmpKDga8w.h
INFO: Status: gcc -E -U __GNUC__ -dD "-Dinline=" "-D__inline__=" "-D__extension__=" "-D__const=const" "-D__asm__(x)=" "-D__asm(x)=" "-DCTYPESGEN=1" "/tmp/tmpKDga8w.h"
INFO: Status: Parsing /tmp/tmpKDga8w.h
ERROR: /usr/include/x86_64-linux-gnu/sys/cdefs.h:248: Syntax error at '\n'
ERROR: /usr/include/assert.h:40: Syntax error at '\n'
INFO: Status: Processing description list.
WARNING: Could not parse macro "#define __ASSERT_VOID_CAST ( void )"
WARNING: Macro "assert" depends on an unknown identifier "__FILE__". Macro "assert" will not be output
WARNING: Macro "assert" depends on an unknown identifier "__LINE__". Macro "assert" will not be output
WARNING: Macro "__ASSERT_FUNCTION" depends on an unknown identifier "__func__". Macro "__ASSERT_FUNCTION" will not be output
WARNING: Macro "static_assert" depends on an unknown identifier "_Static_assert". Macro "static_assert" will not be output
INFO: Status: Writing to stdout.
INFO: Status: Wrapping complete.
Both header files are part of glibc 2.24 (relevant Debian package: libc6-dev 2.24-11+deb9u4). I have noticed that for ctypesgen 1.0.1, the parsing error for sys/cdefs.h does not appear.
Parsing errors also occur for header files of external libraries. For example trying to parse the /usr/include/ext2fs/ext2fs.h of the libext2fs library (e2fslibs-dev 1.43.4-2+deb9u1 on Debian) produces the following parsing errors:
$ ctypesgen /usr/include/ext2fs/ext2fs.h --library libext2fs.so -D __signed__= > /dev/null
...
ERROR: /usr/include/ext2fs/ext2_io.h:86: Syntax error at 'io_stats'
ERROR: /usr/include/ext2fs/ext2_io.h:99: Syntax error at '}'
ERROR: /usr/include/x86_64-linux-gnu/sys/cdefs.h:248: Syntax error at '\n'
[Used -D __signed__= to relieve ctypesgen from parsing it]:
Looking at the ext2_io.h source code, the first parsing error may occur because both type and variable have the same name.
errcode_t (*get_stats)(io_channel channel, io_stats *io_stats);
Are the syntax errors important? Is there any prospect of eliminating the syntax errors from the parsing process or should one just ignore them?