Re: C Program compile error
On Fri, Feb 22, 2002 at 07:16:12AM -0700, Frank Carreiro wrote: > Is there a list someone can suggest I join? Looking for one that can > help answer these kind of questions :-) Somewhere out there there's a list called linux-c-programming...I think it's one of the mailing lists pointed to on kernel.org (not sure, though). A Google search would surely turn it up. I was on it for awhile, and will probably rejoin it soon, as it was very helpful. Regards, Ben -- Ben Logan: ben at wblogan dot net OpenPGP Key KeyID: A1ADD1F0 ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: C Program compile error
> > > >A bit more explanation--although this isn't specifically RedHat, or even >Linux, so it should be on a software development list...so the following >is necessarily simplified. But it should dispell some misconceptions I >think I see. > Is there a list someone can suggest I join? Looking for one that can help answer these kind of questions :-) [snip] > > >That's about as simplified as I can make it, but I hope it helps. > -- > Dave Ihnat > [EMAIL PROTECTED] > Yes Definitely! I appreciate the comments from everyone. Thanks All! Frank ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: C Program compile error
# gcc -o program code.c -lm Make sure you're remembering to include the library at compile time. The math functions are not part of the standard C library :) On Thu, 21 Feb 2002, Frank Carreiro wrote: > Not sure if this is the right list for it but here goes... > > I'm currently learning how to code in C. I'm using a RedHat 7.1 > workstation which when installed I selected to install everything (I > don't like messing with dependancies ::grinz::). I've been including > stdio.h and the last few weeks everything has been happy. The last > couple of days I've been learning about math.h however it's failing when > I try and compile. Getting the following message: > > --- > > In function `main`: > undefined reference to `pow` > collect2: ld returned 1 exit status > > --- > > I'm trying to calculate a value (x) raised to the y power. I suspect > there is a library not found by the linker (wild guess). > > Any thoughts on how I can track this down? > > Thx > > > > > > ___ > Redhat-list mailing list > [EMAIL PROTECTED] > https://listman.redhat.com/mailman/listinfo/redhat-list > -- -Statux ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: C Program compile error
On Thu, Feb 21, 2002 at 02:57:58PM -0500, Trond Eivind Glomsrød wrote: > No, it only declares the symbols and functions. A header file does not > specify linking. > > > Out of curiosity is there a way to compile without specifying -lm? > > > > Just wondering why -lm is required for standard math functions. > > Because libm contains the standard math functions. A bit more explanation--although this isn't specifically RedHat, or even Linux, so it should be on a software development list...so the following is necessarily simplified. But it should dispell some misconceptions I think I see. A program consists of code that is compiled from source into machine executable instructions. If you had to rebuild all source every time you tried to build the program, the development process would be exceedingly time-consuming and tedious; and usually, changes are only to a small portion of the code at any given time. Therefore, it's desirable to do this in stages. Thus, it's possible to compile portions--usually segregated in separate source files--of the program into an intermediate form called an object file. A program called the 'linker' then can combine these intermediate object files into a functioning executable file. When components of the program are separated in this manner, header files provide information about the other portions of the program--such as valid function names, values for arguments, etc.--that need to be used to reference these in the source of any given element. The intermediate object files contain these _external_ references in a form recognizable to the 'linker', which can then reconcile them all when it constructs the final executable. Much code is common--for instance, math functions--and doesn't change between different programs that use it. Thus, common functions are compiled into intermediate object form, and the resulting files are grouped together in an object library for convenience. The linker knows how to select just the objects it needs from the library. That's about as simplified as I can make it, but I hope it helps. -- Dave Ihnat [EMAIL PROTECTED] ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
C Program compile error
Not sure if this is the right list for it but here goes... I'm currently learning how to code in C. I'm using a RedHat 7.1 workstation which when installed I selected to install everything (I don't like messing with dependancies ::grinz::). I've been including stdio.h and the last few weeks everything has been happy. The last couple of days I've been learning about math.h however it's failing when I try and compile. Getting the following message: --- In function `main`: undefined reference to `pow` collect2: ld returned 1 exit status --- I'm trying to calculate a value (x) raised to the y power. I suspect there is a library not found by the linker (wild guess). Any thoughts on how I can track this down? Thx ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: C Program compile error
Frank Carreiro <[EMAIL PROTECTED]> writes: > That worked thanks :-) > > I've read through the gcc man page and didn't see the -lm option. In > my source as I understand it #include should have done it. No, it only declares the symbols and functions. A header file does not specify linking. > Out of curiosity is there a way to compile without specifying -lm? > > Just wondering why -lm is required for standard math functions. Because libm contains the standard math functions. -- Trond Eivind Glomsrød Red Hat, Inc. ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: C Program compile error
That worked thanks :-) I've read through the gcc man page and didn't see the -lm option. In my source as I understand it #include should have done it. Out of curiosity is there a way to compile without specifying -lm? Just wondering why -lm is required for standard math functions. Thanks again! Frank Frank Carreiro <[EMAIL PROTECTED]> writes: [snip] >> >> --- >> >> In function `main`: >> undefined reference to `pow` >> collect2: ld returned 1 exit status >> >> --- >> >> I'm trying to calculate a value (x) raised to the y power. I suspect >> there is a library not found by the linker (wild guess). >> >> Any thoughts on how I can track this down? > "-lm" (link with the standard math library) -- Trond Eivind Glomsrød Red Hat, Inc. ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: C Program compile error
Frank Carreiro <[EMAIL PROTECTED]> writes: > Not sure if this is the right list for it but here goes... > > I'm currently learning how to code in C. I'm using a RedHat 7.1 > workstation which when installed I selected to install everything (I > don't like messing with dependancies ::grinz::). I've been including > stdio.h and the last few weeks everything has been happy. The last > couple of days I've been learning about math.h however it's failing > when I try and compile. Getting the following message: > > --- > > In function `main`: > undefined reference to `pow` > collect2: ld returned 1 exit status > > --- > > I'm trying to calculate a value (x) raised to the y power. I suspect > there is a library not found by the linker (wild guess). > > Any thoughts on how I can track this down? "-lm" (link with the standard math library) -- Trond Eivind Glomsrød Red Hat, Inc. ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: C Program compile error
On Thu, 21 Feb 2002 11:17:40 -0700 Frank Carreiro <[EMAIL PROTECTED]> wrote: > I try and compile. Getting the following message: > > --- > > In function `main`: > undefined reference to `pow` > collect2: ld returned 1 exit status > > --- > > I'm trying to calculate a value (x) raised to the y power. I suspect > there is a library not found by the linker (wild guess). > > Any thoughts on how I can track this down? > > Thx $ apropos pow README.machten [perlmachten] (1) - Perl version 5 on Power MachTen systems apm (1) - query Advanced Power Management (APM) BIOS apmd (8) - Advanced Power Management (APM) daemon exp (3) - exponential, logarithmic and power functions ldexp(3) - multiply floating-point number by integral power of 2 log [exp](3) - exponential, logarithmic and power functions log10 [exp] (3) - exponential, logarithmic and power functions pow [exp](3) - exponential, logarithmic and power functions poweroff [halt] (8) - stop the system Then look at the manpage for the pow function >From the manpage EXP(3) Linux Programmer's Manual EXP(3) NAME exp, log, log10, pow - exponential, logarithmic and power functions SYNOPSIS #include The pow function is in math.h Regards, Jim H msg72484/pgp0.pgp Description: PGP signature
