Hi, When you compile a library function into your program the system has to be told in which libraries to look for these references during linking. A small set of libraries such as stdio are always checked for by the compiler - but it doesn't check all the libraries for references to functions as this would take *way* too long.
If your library is in the standard place of /lib/ then you only have to specify it's short name, if it is in a non-standard place you have to specify the full path eg /home/steve/lib. The standard places to look are defined for the system with ldconfig. So you should be able to compile with: gcc -Wall -o it it.c -lm The -l is for link and the m is the shortest name for the library which is unique e.g lib<name>.<major>.<minor>. There is some explanation of why the library has to come last but I can't remember! If your gonna spend any time programming yourself I'd recommend the Prgogramming with Free Software from O'Reilly or Beginning Linux Programming from Wrox. Generally I haven't been able to find comparable 'easy to read' web content :( HTH Steve On Sun, Jul 04, 1999 at 05:10:59PM +0100, Andrew Holmes wrote: > Hi, > > I've been trying to compile a c program which uses maths functions like pow() > and cbrt(), I've included the #include <math.h> and it compiles to an object > ok. However when I try to compile it to a program I get: > > /tmp/ccc13322: In function `difi': > /tmp/ccc13322(.text+0xea): undefined reference to `cbrt' > > Am I supposed to use some command line to gcc to make it work, I've been > using > > gcc -o it it.c > > to make a program called 'it' from the source 'it.c' > > Any help would be greatly appreciated, TIA > -- > Best Wishes, > Andy Holmes <[EMAIL PROTECTED]> > > We are MicroSoft. You will be assimilated. Resistance is futile. > -- Attributed to B.G., Gill Bates > > > -- > Unsubscribe? mail -s unsubscribe [EMAIL PROTECTED] < /dev/null >
