Build ZLIB with fvisibility=hidden on Linux

[cyrillicw]

There is a macro ZEXPORT which as I understand should set appropriate visibility for functions that should be accessed from outside. But for Linux definition of ZEXPORT is empty so when I set fvisibility=hidden the functions become invisible

[fredgan]

You can build with your own ZEXPORT MACRO if you set fvisibility=hidden globally. But why you set fvisibility=hidden ?

[cyrillicw]

Oh, thank you, didn't think about the possibility of defining own ZEXPORT. Thank you! I use fvisibility=hidden because according to https://gcc.gnu.org/wiki/Visibility this can significantly influence the size of the executable, compilation time, etc.

[uis246]

ZEXPORT for some reason is placed in the middle of function declarations and definitions instead of at the beginning, which causes compiler to spit warnings and sometimes to ignore attribute.