makefile - make 文件中的 -wl, --start-group 是什么意思？

Question

我的 Make 文件中有这个..

# Create list of object files
#
LIB_OBJS =  -Wl,--start-group \
$(T_OBJ_DIR)/Source1.o \
$(T_OBJ_DIR)/Source2.o \
$(T_OBJ_DIR)/Source3.o \
$(T_OBJ_DIR)/Source4.o \
$(T_OBJ_DIR)/Source5.o \
-Wl,--end-group \

谁能解释一下“-Wl，--start-group”和“-Wl，--end-group”是什么意思？

Answer 1

这些是链接器的标志(这就是 -Wl 的含义)，因此 ld (链接器)的文档将解释其余部分。

来自man page对于 GNU ld:

-( archives -)

--start-group archives --end-group

The archives should be a list of archive files. They may be either explicit file names, or -l options.

The specified archives are searched repeatedly until no new undefined references are created. Normally, an archive is searched only once in the order that it is specified on the command line. If a symbol in that archive is needed to resolve an undefined symbol referred to by an object in an archive that appears later on the command line, the linker would not be able to resolve that reference. By grouping the archives, they all be searched repeatedly until all possible references are resolved.

Using this option has a significant performance cost. It is best to use it only when there are unavoidable circular references between two or more archives.