The bug referenced in os-win32.h was fixed in mingw-w64 v6. According to repology, version 5 used by ubuntu 18, which is not yet out of support, so provide a meson link test for it.
Signed-off-by: Richard Henderson <richard.hender...@linaro.org> --- meson.build | 12 ++++++++++++ include/sysemu/os-win32.h | 16 +++++++++------- 2 files changed, 21 insertions(+), 7 deletions(-) diff --git a/meson.build b/meson.build index 282e7c4650..f22a09dac5 100644 --- a/meson.build +++ b/meson.build @@ -2018,6 +2018,18 @@ foreach k, v: config_host endif endforeach +# Older versions of MinGW do not import _lock_file and _unlock_file properly. +# This was fixed for v6.0.0 with commit b48e3ac8969d. +if targetos == 'windows' + config_host_data.set('HAVE__LOCK_FILE', cc.links(''' + #include <stdio.h> + int main(void) { + _lock_file(NULL); + _unlock_file(NULL); + return 0; + }''', name: '_lock_file and _unlock_file')) +endif + ######################## # Target configuration # ######################## diff --git a/include/sysemu/os-win32.h b/include/sysemu/os-win32.h index 770752222a..649f417d39 100644 --- a/include/sysemu/os-win32.h +++ b/include/sysemu/os-win32.h @@ -113,20 +113,22 @@ static inline char *realpath(const char *path, char *resolved_path) return resolved_path; } -/* ??? Mingw appears to export _lock_file and _unlock_file as the functions - * with which to lock a stdio handle. But something is wrong in the markup, - * either in the header or the library, such that we get undefined references - * to "_imp___lock_file" etc when linking. Since we seem to have no other - * alternative, and the usage within the logging functions isn't critical, - * ignore FILE locking. +/* + * Older versions of MinGW do not import _lock_file and _unlock_file properly. + * This was fixed for v6.0.0 with commit b48e3ac8969d. */ - static inline void qemu_flockfile(FILE *f) { +#ifdef HAVE__LOCK_FILE + _lock_file(f); +#endif } static inline void qemu_funlockfile(FILE *f) { +#ifdef HAVE__LOCK_FILE + _unlock_file(f); +#endif } /* We wrap all the sockets functions so that we can -- 2.25.1