Shared libraries on Alpha

["K. Holcomb" <kholcomb at cs dot virginia dot edu>]

Hello,

I am sending this to the general list because we are not certain whether this
is a bug in gcc or something else, or even a problem on our part.  We have a 
large, complex application that is failing on Alpha systems upgraded to 
RedHat 6.1 with a further upgrade to gcc 2.95.2, but which works on older 
systems as well as on upgraded Intels.  The problem *seems* to be that 
gettimeofday returns different results depending on whether it is called via 
a statically linked or a dynamic library.  The static linking works; dynamic 
does not.  It appears that dynamic libraries are using a 32-bit implementation 
of gettimeofday, whereas the other cases invoke a 64-bit implementation.
We'd be grateful for any suggestions or information; has anybody else seen
anything similar on Alphas?

The attached short test program reproduces the problem:

----------------------------------------------------------------------------

test_get_time.c:
----------------

#include <stdio.h>
#include <unistd.h>
#include <sys/time.h>

extern struct timeval get_time();

int main(int argc, char **argv) 
{
  struct timeval  now;
  int ret, i;
  char time_array[16];

  for (i = 0; i < 16; i++)
    {
      time_array[i] = 0;
    }

  ret = gettimeofday(&now, 0);
  fprintf(stderr, "Time in main program:\nret = %d\n", ret);
  fprintf(stderr, "now = %ld.%ld\n", now.tv_sec, now.tv_usec);
  fprintf(stderr, "now = %d.%d\n", now.tv_sec, now.tv_usec);

  ret = gettimeofday((struct timeval *) time_array, 0);
  fprintf(stderr, "IN test_get_time(): ret = %d.  Char array = \n", ret);
  for (i = 0; i < 16; i++)
    {
      fprintf(stderr, "byte %d = %x\n", i, time_array[i]);
    }

  now = get_time();
  fprintf(stderr, "Time from function call:\n");
  fprintf(stderr, "now = %ld.%ld\n", now.tv_sec, now.tv_usec);
  fprintf(stderr, "now = %d.%d\n", now.tv_sec, now.tv_usec);

}

---------------------------------------

get_time_func.c:
----------------

#include <stdio.h>
#include <unistd.h>
#include <sys/time.h>

struct timeval get_time()
{
  struct timeval  now;
  int ret, i;
  char time_array[16];


  ret = gettimeofday(&now, 0);
  fprintf(stderr, "IN get_time(): ret = %d\n", ret);
  fprintf(stderr, "now = %ld.%ld\n", now.tv_sec, now.tv_usec);
  fprintf(stderr, "now = %d.%d\n", now.tv_sec, now.tv_usec);
  for (i = 0; i < 16; i++)
    {
      time_array[i] = 0;
    }

  ret = gettimeofday((struct timeval *) time_array, 0);
  fprintf(stderr, "IN get_time(): ret = %d.  Char array = \n", ret);
  for (i = 0; i < 16; i++)
    {
      fprintf(stderr, "byte %d = %x\n", i, time_array[i]);
    }
  return now;
}

-----------------------------------------

makefile:
--------

CC	= gcc
RM	= /bin/rm -f 
SRC_DIR	= .
BIN_DIR	= .
LIB_DIR	= .
OBJ_DIR	= .
CFLAGS	= -I. -v

BINARIES	=	$(BIN_DIR)/test_get_time

OBJECTS		=	$(OBJ_DIR)/get_time_func.o

LIBRARY		=	$(LIB_DIR)/libGetTime.a

SHARED_LIBRARY		=	$(LIB_DIR)/libGetTime.so

all: 
	make $(OBJECTS)
	make $(LIBRARY)
	make $(SHARED_LIBRARY)
	make $(BINARIES)

clean:
	-$(RM) $(LIBRARY)
	-$(RM) $(SHARED_LIBRARY)
	-$(RM) $(OBJECTS)
	-$(RM) $(BINARIES)


$(LIBRARY):	$(OBJECTS)
	ar crv $(LIBRARY) $(OBJECTS)

$(SHARED_LIBRARY):	$(OBJECTS)
	-ld -o $(SHARED_LIBRARY)  -shared $(OBJECTS) $(SO_LIB_FLAGS) 

$(OBJ_DIR)/get_time_func.o: $(SRC_DIR)/get_time_func.c
	$(CC) $(CFLAGS) -fpic -c $(SRC_DIR)/get_time_func.c -o $@

$(BIN_DIR)/test_get_time: $(OBJ_DIR)/get_time_func.o $(SRC_DIR)/test_get_time.c
	$(CC) $(CFLAGS) $(SRC_DIR)/test_get_time.c -L. -lGetTime -o $@