Have Geek Brain

Argument order in cygwin gcc 4.3 matters when linking with glib-2.0

I am trying to compile code that works on os x and linux using cygwin. However, I find that the order of the gcc arguments gives unexpected results.

For example, the following is true:

gcc -std=gnu99 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -lglib-2.0 -lintl -liconv -fgnu89-inline -fno-leading-underscore -o nb-learn.exe nb-learn.c

but the following works:

gcc -std=gnu99 -fgnu89-inline -fno-leading-underscore -o nb-learn.exe nb-learn.c -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -lglib-2.0 -lintl -liconv

Can anyone explain how this works? Also, are there methods or code I can look at to force autoconf to change the order of its arguments based on platform?

Here are the first two lines of the error message:

/cygdrive/c/Users/aischein/AppData/Local/Temp/cc9MvUsf.o:nb-learn.c:(.text+0x260): undefined reference to `_g_hash_table_size'
/cygdrive/c/Users/aischein/AppData/Local/Temp/cc9MvUsf.o:nb-learn.c:(.text+0x29c): undefined reference to `_g_hash_table_get_keys'

Thank,

SetJmp (gcc 4.3.4)

+2


a source to share


1 answer


GCC documentation says:

-l

<i> Library

-l

library

Searches a library named library when linking. (The second alternative, with the library as a separate argument, is for POSIX compliance only and is not recommended.)

It matters when you write this option in a command; the linker searches for and processes libraries and object files in the order in which they are listed.

Thus, ' foo.o -lz bar.o

' searches for a library z

'' after the file foo.o

, but before bar.o

. If it bar.o

refers to functions in ` z

', these functions may not be loaded.




Options -Wl,--start-group

and are -Wl,--end-group

sometimes useful to prevent such problems.


None of this is a problem if you only use shared libraries.

+2


a source






More articles:


All Articles