View Single Post
Old 2020-12-09, 01:48   #4
mathwiz
 
Mar 2019

2258 Posts
Default

Possibly helpful? https://gcc.gnu.org/gcc-10/porting_to.html

"A common mistake in C is omitting extern when declaring a global variable in a header file. If the header is included by several files it results in multiple definitions of the same variable. In previous GCC versions this error is ignored. GCC 10 defaults to -fno-common, which means a linker error will now be reported. To fix this, use extern in header files when declaring global variables, and ensure each global is defined in exactly one C file."

Last fiddled with by mathwiz on 2020-12-09 at 01:49 Reason: quote relevant part of page
mathwiz is offline   Reply With Quote