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Hello, |
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|
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On Sun, 02 Oct 2016, Meino.Cramer@×××.de wrote: |
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>Suppose I would compile a program, which uses shared libraries and I |
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>specify an additional library, which will be completly unused by the |
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>code...will the resulting executable differ from an executable which |
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>is compiled without this library ? |
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|
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Suppose you'd just test it? |
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|
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$ echo 'int main(void) {return 0;}' > t.c |
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$ gcc -o t_nolib t.c |
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$ gcc -o t_lib -lglib t.c |
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$ gcc -o t_lib_as -Wl,-as-needed -lglib t.c |
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$ gcc -o t_lib_nas -Wl,-no-as-needed -lglib t.c |
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$ cmp t_nolib t_lib_as; echo $? |
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0 |
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|
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|
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$ ls -l |
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-rw-r----- 1 dh dh 27 Oct 2 05:40 t.c |
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-rwxr-x--- 1 dh dh 6824 Oct 2 05:40 t_lib |
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-rwxr-x--- 1 dh dh 6424 Oct 2 05:40 t_lib_as |
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-rwxr-x--- 1 dh dh 6824 Oct 2 05:40 t_lib_nas |
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-rwxr-x--- 1 dh dh 6424 Oct 2 05:40 t_nolib |
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|
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$ ldd t_* |
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t_lib: |
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linux-vdso.so.1 (0x00007fff0b7ff000) |
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libglib-1.2.so.0 => /usr/lib64/libglib-1.2.so.0 (0x00007f372b55b000) |
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libc.so.6 => /lib64/libc.so.6 (0x00007f372b1bb000) |
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libdl.so.2 => /lib64/libdl.so.2 (0x00007f372afb7000) |
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/lib64/ld-linux-x86-64.so.2 (0x00007f372b793000) |
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t_lib_as: |
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linux-vdso.so.1 (0x00007fffadf70000) |
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libc.so.6 => /lib64/libc.so.6 (0x00007ff9289d7000) |
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/lib64/ld-linux-x86-64.so.2 (0x00007ff928d77000) |
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t_lib_nas: |
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linux-vdso.so.1 (0x00007fffe9e6f000) |
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libglib-1.2.so.0 => /usr/lib64/libglib-1.2.so.0 (0x00007f2a43afb000) |
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libc.so.6 => /lib64/libc.so.6 (0x00007f2a4375b000) |
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libdl.so.2 => /lib64/libdl.so.2 (0x00007f2a43557000) |
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/lib64/ld-linux-x86-64.so.2 (0x00007f2a43d33000) |
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t_nolib: |
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linux-vdso.so.1 (0x00007fffbed58000) |
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libc.so.6 => /lib64/libc.so.6 (0x00007fe55b4f4000) |
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/lib64/ld-linux-x86-64.so.2 (0x00007fe55b894000) |
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|
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So: YES, it will differ unless you use the "-as-needed" ld flag. Which |
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is why some distros have -as-needed as a default linker flag, to prune |
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deps of packages, even though it causes "trouble" at times ... |
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|
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-dnh |
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|
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-- |
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Graphisch??? Wie meinen? Hast du zuviel Fleisch von zu "gluecklichen" |
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Rindern gefuttert? *scnr* Wozu zum Henker sollte man sowas brauchen? |
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Logo ginge auch per ASCII :) (Logo? welches Logo? Wozu ueberhaupt?) |
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[David Haller in suse-linux] |
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