Thanks for the answer. The choice to compile in 64 bits comes from our customer even though we can advise him not to. Our priority on this application is performance and stability. I was wondering if using 32 bits binaries under a 64 bit os would slow down the execution (as the os deals with 64 bits blocks). If you have any idea about that. About your last point, i'm affraid i don't have the choice. The signature of our mails is added by our mail server, so we cannot decide wether to put it or not. Regards, Samuel ----- Original Message ----- From: "David Edelsohn" <dje@xxxxxxxxxxxxxx> To: "Samuel Gaudard" <sgaudard@xxxxxxxxxxxx> Cc: <gcc-help@xxxxxxxxxxx> Sent: Friday, December 03, 2004 6:43 AM Subject: Re: question about compiling in a 64 bits system > >>>>> Samuel Gaudard writes: > > > I'm porting an application from AIX 4.3 (32 bits) to AIX 5.2 (64 bits). So > > i have to recompile all my source files. > > I've installed gcc 3.3.2.0 on the new server. > > If i compile using : gcc -g -o example example.c , will it compile in 64 > > bits mode ? (as the os is 64 bits) > > > > Do i have to compile using the -maix64 flag ? > > > > eg : gcc -maix64 -g -o example example.c > > to get a 64 bit binary? > > [It helps to mention AIX in the subject line when one asks an > AIX-specific question.] > > AIX 4.3 supports both 64 bit applications (on 64 bit systems) and > 32 bit applications. AIX 5.2 also supports both 32 bit applications and > 64 bit applications. > > GCC defaults to 32 bit mode when compiling for AIX. There is no > reason to compile an application in 64 bit mode unless one needs a > specific 64 bit feature (64 bit addressing or fast 64 bit integer > computation). > > Most applications compiled on AIX 4.3 will run on AIX 5.2 without > recompilation. Recompiling may help with some functionality. > > aix52$ gcc -g -o example example.c > > will produce a 32 bit executable that will run on AIX 5.2. > > aix52$ gcc -maix64 -g -o example example.c > > will produce a 64 bit executable that will run on AIX 5.2, but there is no > reason to use the -maix64 option if the application does not need it. > > David > > P.S. Please do not send messages to public mailinglists with > boilerplate that the "message contains information that may be privileged > or confidential". This message contains information that may be privileged or confidential and is the property of the Capgemini Group. It is intended only for the person to whom it is addressed. If you are not the intended recipient, you are not authorized to read, print, retain, copy, disseminate, distribute, or use this message or any part thereof. If you receive this message in error, please notify the sender immediately and delete all copies of this message.
