{"id":1056,"date":"2008-03-28T21:49:34","date_gmt":"2008-03-28T11:49:34","guid":{"rendered":"http:\/\/www.flamingspork.com\/blog\/2008\/03\/28\/dear-lazyweb-autoconf-and-define-have_-0\/"},"modified":"2008-03-28T21:49:34","modified_gmt":"2008-03-28T11:49:34","slug":"dear-lazyweb-autoconf-and-define-have_-0","status":"publish","type":"post","link":"https:\/\/www.flamingspork.com\/blog\/2008\/03\/28\/dear-lazyweb-autoconf-and-define-have_-0\/","title":{"rendered":"Dear LazyWeb, autoconf and #define HAVE_ 0"},"content":{"rendered":"

How do I make an existing project (let’s say, MySQL) switch from generating a config.h that has #undef HAVE_FOO to one that generates #define HAVE_FOO 0 instead?<\/p>\n

Why? Well, here’s why:<\/p>\n

Testing for features should be done by including “config.h” and using #if HAVE_<feature><\/tt>. Use of #if<\/tt> (rather than #ifdef<\/tt>) allows the gcc -Wundef flag to warn users about features which aren’t defined 1 or 0 in config.h.<\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":"

How do I make an existing project (let’s say, MySQL) switch from generating a config.h that has #undef HAVE_FOO to one that generates #define HAVE_FOO 0 instead? Why? Well, here’s why: Testing for features should be done by including “config.h” … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[1],"tags":[],"class_list":["post-1056","post","type-post","status-publish","format-standard","hentry","category-general"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p5a6n8-h2","jetpack-related-posts":[{"id":411,"url":"https:\/\/www.flamingspork.com\/blog\/2005\/05\/24\/dont-you-just-love-being-compatible\/","url_meta":{"origin":1056,"position":0},"title":"Don’t you just love being compatible?","author":"Stewart Smith","date":"2005-05-24","format":false,"excerpt":"\/* Force server down. kill all connections and threads and exit *\/ #if defined(OS2) || defined(__NETWARE__) extern \"C\" void kill_server(int sig_ptr) #define RETURN_FROM_KILL_SERVER DBUG_VOID_RETURN #elif !defined(__WIN__) static void *kill_server(void *sig_ptr) #define RETURN_FROM_KILL_SERVER DBUG_RETURN(0) #else static void __cdecl kill_server(int sig_ptr) #define RETURN_FROM_KILL_SERVER DBUG_VOID_RETURN #endif { DBUG_ENTER(\"kill_server\"); (from sql\/mysqld.cc) There just has\u2026","rel":"","context":"In "mysql"","block_context":{"text":"mysql","link":"https:\/\/www.flamingspork.com\/blog\/category\/work-et-al\/mysql\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":1777,"url":"https:\/\/www.flamingspork.com\/blog\/2010\/01\/09\/shocked-and-stunned-that-code-exists-and-does-work\/","url_meta":{"origin":1056,"position":1},"title":"Shocked and Stunned (that code exists and does work)","author":"Stewart Smith","date":"2010-01-09","format":false,"excerpt":"#define READ_ALL 1 \/* openfrm: Read all parameters *\/ #define EXTRA_RECORD 8 \/* Reservera plats f|r extra record *\/ \u00ef\u00bb\u00bf\u00ef\u00bb\u00bfand later on.... \u00c2\u00a0\u00c2\u00a0if (prgflag & (READ_ALL+EXTRA_RECORD)) \u00c2\u00a0\u00c2\u00a0 \u00c2\u00a0records++; Feel free to think about that for a second. (I have an urge to add this to questions asked in a job\u2026","rel":"","context":"In "code"","block_context":{"text":"code","link":"https:\/\/www.flamingspork.com\/blog\/category\/code\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":1145,"url":"https:\/\/www.flamingspork.com\/blog\/2008\/07\/10\/wl4271-encrypted-online-backup-preview-3\/","url_meta":{"origin":1056,"position":2},"title":"WL4271 Encrypted Online Backup: Preview 3","author":"Stewart Smith","date":"2008-07-10","format":false,"excerpt":"\u00e2\u20ac\u0153WL4271 Encrypted Online Backup: Preview 3\u00e2\u20ac\u009d branch in Launchpad Now with Windows support. Many thanks to Chuck Bell for helping get the code going on Windows. We can however, all sit around dumbfounded as to how Windows has so little of a POSIX like layer and yet doesn't define ENOTSUP.\u2026","rel":"","context":"In "mysql"","block_context":{"text":"mysql","link":"https:\/\/www.flamingspork.com\/blog\/category\/work-et-al\/mysql\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":101,"url":"https:\/\/www.flamingspork.com\/blog\/2003\/06\/04\/finally-fixed-it\/","url_meta":{"origin":1056,"position":3},"title":"finally! fixed it!","author":"Stewart Smith","date":"2003-06-04","format":false,"excerpt":"From: Stewart Smith Date: Wed Jun 4, 2003 3:56:09 PM Australia\/Melbourne To: Linus Torvalds Cc: linux-kernel@vger.kernel.org, David Woodhouse , Stewart Smith Subject: [PATCH] fixed: CRC32=y && 8193TOO=m unresolved symbols Linus, please apply - this fixes unresolved symbols when CONFIG_CRC32=y and CONFIG_8139TOO=m (it also appeared on some other ethernet device drivers).\u2026","rel":"","context":"In "linux-kernel"","block_context":{"text":"linux-kernel","link":"https:\/\/www.flamingspork.com\/blog\/category\/linux-kernel\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":3231,"url":"https:\/\/www.flamingspork.com\/blog\/2013\/03\/03\/unireg-h-is-gone\/","url_meta":{"origin":1056,"position":4},"title":"unireg.h is finally gone","author":"Stewart Smith","date":"2013-03-03","format":false,"excerpt":"I got rid of unireg.cc way back in 2009 as I rewrote all the FRM related code inside Drizzle to instead use a nice protobuf based structure. If you're wondering what was there, I just quote this part of pack_screens() from unireg.cc in MySQL 5.6: start_row=4; end_row=22; cols=80; fields_on_screen=end_row+1-start_row; We\u2026","rel":"","context":"In "drizzle"","block_context":{"text":"drizzle","link":"https:\/\/www.flamingspork.com\/blog\/category\/work-et-al\/drizzle-work-et-al\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":1067,"url":"https:\/\/www.flamingspork.com\/blog\/2008\/04\/10\/twitter-updates-for-2008-04-10\/","url_meta":{"origin":1056,"position":5},"title":"Twitter Updates for 2008-04-10","author":"Stewart Smith","date":"2008-04-10","format":false,"excerpt":"@cafeugo: i think there's a #define somewhere for the max number of tables in a join... although casually surprised it performs well at ... # Powered by Twitter Tools.","rel":"","context":"In "Twitter"","block_context":{"text":"Twitter","link":"https:\/\/www.flamingspork.com\/blog\/category\/from-twitter\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]}],"jetpack_likes_enabled":true,"_links":{"self":[{"href":"https:\/\/www.flamingspork.com\/blog\/wp-json\/wp\/v2\/posts\/1056","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.flamingspork.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.flamingspork.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.flamingspork.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.flamingspork.com\/blog\/wp-json\/wp\/v2\/comments?post=1056"}],"version-history":[{"count":0,"href":"https:\/\/www.flamingspork.com\/blog\/wp-json\/wp\/v2\/posts\/1056\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.flamingspork.com\/blog\/wp-json\/wp\/v2\/media?parent=1056"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.flamingspork.com\/blog\/wp-json\/wp\/v2\/categories?post=1056"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.flamingspork.com\/blog\/wp-json\/wp\/v2\/tags?post=1056"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}