bugflux.org » c http://bugflux.org AndrĂ© Prata, nDray Fri, 16 Sep 2011 07:54:03 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 casting malloc… http://bugflux.org/blog/580:casting-malloc/ http://bugflux.org/blog/580:casting-malloc/#comments Mon, 20 Apr 2009 21:39:36 +0000 nDray http://bugflux.org/?p=580 Continue reading →]]> … is a matter most c programmers have questioned themselves about once or twice, at least, by now. to do or not to do, that is the question! i have been recently penalized by 2.5 percent in a program, along with a colleague, by not casting the result of the malloc function (a pointer to void, void *) to whatever type we want to use. we have questioned ourselves sometimes before the submission of the work, and so we went and searched for it on google. small forum conversations and programming tutorials suggested that this was no longer necessary, since the void pointer was created to leave the char pointer behind as the arbitrary pointer to objects (data). that was when we decided not to cast.

so today, a few weeks later, the teacher tells us (sorry, we asked!!) we lost some points by not casting the attribution from malloc. so i grabbed the rationale for the ansi c programming language, where two things are clearly stated:

  1. the pointer to void is a generic pointer, an invention by the ansi comitee to drop the usage of char * as the arbitrary object pointer;
  2. a pointer to void may be converted to a pointer to any object of any type and vice-versa. even more, the result of the opposite operation compares equal do the original pointer.

a further reading of the text points the reader in the direction that the conversion is done by simple operations, assignment included, not explicit casts.

so, as many people has been preaching in the internet, casting a pointer to void only grants that the user is demanding the compiler to do something it would do anyway. more than that, casting makes you write more code and, when changing code, makes it easier to produce hard to find bugs (imagine you cast, then you change data types, but not the cast!). so, since i’m more or less an advocate of the suckless philosophy, i’m not casting!

]]> http://bugflux.org/blog/580:casting-malloc/feed/ 0 setsolver… http://bugflux.org/blog/12:setsolver/ http://bugflux.org/blog/12:setsolver/#comments Mon, 26 May 2008 22:15:26 +0000 nDray http://bugflux.org/wp/?p=18 Continue reading →]]> … solves set games
download version 20080411

this program was written to compete in a programming challenge. it did not finish in first place, but it was competing with multitasking software! i really think the idea of my program would be killer, and still think it is, the way i encoded the cards and solved their matching. the program is useless, but the idea is worth sharing!

]]> http://bugflux.org/blog/12:setsolver/feed/ 0 lockx… http://bugflux.org/blog/9:lockx/ http://bugflux.org/blog/9:lockx/#comments Sat, 24 May 2008 20:16:10 +0000 nDray http://bugflux.org/wp/?p=15 Continue reading →]]> … locks your screen until the user’s password is typed
download version 20080829 and PKGBUILD.

heavily based on slock, it’s meant to lock X11 sessions.

unlike slock, it doesn’t need you to press enter in order to validate the password, neither to clear the input when you mistype. instead it just reads the characters and if you inputted your password correctly it will unlock the session.

it might take a bit to unlock the session because power the state imposed sometimes require a few seconds to recover.

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