Re: gettimeofday does not link with g++

[Brian Dessent]

Sam Steingold wrote:

> /home/sds/src/clisp/current/build-gxx-g/../src/time.d:75: undefined reference 
> to `rpl_gettimeofday(timeval*, void*)'
> time.o: In function `C_sleep()':
> /home/sds/src/clisp/current/build-gxx-g/../src/time.d:503: undefined 
> reference to `rpl_gettimeofday(timeval*, void*)'
> /home/sds/src/clisp/current/build-gxx-g/../src/time.d:529: undefined 
> reference to `rpl_gettimeofday(timeval*, void*)'
> collect2: ld returned 1 exit status
> 
> nm  gllib/gettimeofday.o
>                  U gettimeofday
> 0000000000000000 T rpl_gettimeofday
> 
> note that the error message lists the arglist of rpl_gettimeofday.

That means that the function had C++ linkage and hence its assembler
name was mangled to encode its type, and the linker is helpfully
demangling the name for display purposes.  If you run "nm time.o" I bet
you'll see the symbol's real asmname shown as
"_Z16rpl_gettimeofdayP7timevalPv" or similar, which explains why it
can't be resolved by the symbol in gettimeofday.o with C linkage.

> when I remove gllib/uniwidth/width.o from the command line, I get
> 
> charstrg.o: In function `char_width(chart)':
> /home/sds/src/clisp/current/build-gxx-g/../src/charstrg.d:324: undefined 
> reference to `uc_width'
> 
> without the arglist of uc_width.

The uniwidth.h header declares uc_width in an extern "C" block to ensure
it has C linkage when built with a C++ compiler.

> any ideas?

It looks like lib/sys_time.in.h needs the same 'extern "C"' treatment.

Brian