Getting Verbose Output with -v
The -voption makes a compiler display the verbose information. This is useful for viewing how the compiler calls ld. For example, using the -voption with the C compiler shows that it automatically links with libc.
$ cc -v himom.c
/opt/ansic/lbin/ecom -ia64abi all -architecture 32 -ext on -lang c \
-exception off -sysdir /usr/include -inline_power 1 -link_type dynamic \ -fpeval float -tls_dyn on -target_os 11.23 -- sys_include /usr/include \ -D__hpux -D__unix -D__ia64=1 -D_BIG_ENDIAN=1 -D_ILP32 -D__HP_cc=60200 \ -D__STDC_EXT__ -D_HPUX_SOURCE -D_INCLUDE_LONGLONG -D_INLINE_ASM \ -D_BIND_LIBCALLS -D_Math_errhandling=MATH_ERREXCEPT -D_FLT_EVAL_METHOD=0 \ -ucode hdriver=optlevel%1% -plusolistoption -O106const! -plusolistoption \ -O113moderate! -plusooption -Oq01,al,ag,cn,sz,ic,vo,Mf,Po,es,rs,Rf,Pr,sp,\ in,cl,om,vc,pi,fa,pe,rr,pa,pv,nf,cp,1x,Pg,ug,1u,lb,uj,dn,sg,pt,kt,em,np,\ ar,rp,dl,fs,bp,wp,pc,mp,lr,cx,cr,pi,so,Rc,fa,ft,fe,ap,st,lc,Bl,sr,ib,pl,\ sd,ll,rl,dl,Lt,ol,fl,lm,ts,rd,dp,If! himom.c LPATH=/usr/lib/hpux32:/opt/langtools/lib/hpux32
/usr/ccs/bin/ld -o a.out -u__exit -umain himom.o -lc removing /var/tmp/AAAa17931
removing himom.o
Passing Linker Options from the Compiler Command with -Wl
The -Wloption passes options and arguments to ld directly, without the compiler interpreting the options. Its syntax is:
-Wl,arg1 [,arg2]...
where each argn is an option or argument passed to the linker. For example, to make ld use the archive version of a library instead of the shared, you must specify -a archive on the ld command line before the library.
Example Using -Wl
The command for instructing the linker to use an archive version of libm from the C command line is:
$ cc -Aa mathprog.c -Wl,-a,archive,-lm,-a,default
The command for instructing the linker to use an archive version of libm is:
$ $ ld /opt/langtools/lib/crt0.o mathprog.o -a archive -lm -a default -lc
Renaming the Output File with -o
The -oname option causes ld to name the output file name instead of a.out. For example, to compile a C program prog.c and name the resulting file sum_num:
$ cc -Aa -o sum_num prog.c | //Compile | using -o | option. |
$ sum_num | //Run the | program. | |
Enter a | number to sum: 5 | | | |
The sum | of 1 to 5: 15 | | | |
Specifying Libraries with -l
Sometimes programs call routines not contained in the default libraries. In such cases you must explicitly specify the necessary libraries on the compile line with the -loption. The compilers pass -loptions directly to the linker before any default libraries, such as libc.
For example, if a C program calls library routines in the curses library (libcurses), you must specify -lcurseson the cc command line: .