5.3.3 Global/Globl Directives

The .global symbol
 (and its alias, .globl symbol) directive declares a symbol that is defined in the current module and is available to other modules. .global makes the symbol visible to the linker. If you define symbol in your partial program, its value is made available to other partial programs that are linked with it. Otherwise, symbol takes its attributes from a symbol of the same name from another file linked into the same program.