genode/repos/libports/lib/mk/posix.mk

SRC_CC = construct.cc

LIBS += libc

SHARED_LIB = yes

vpath construct.cc $(REP_DIR)/src/lib/posix
Simpify startup of dynamically linked binaries This patch removes the component_entry_point library, which used to proved a hook for the libc to intercept the call of the 'Component::construct' function. The mechansim has several shortcomings (see the discussion in the associated issue) and was complex. So we eventually discarded the approach in favor of the explicit handling of the startup. A regular Genode component provides a 'Component::construct' function, which is determined by the dynamic linker via a symbol lookup. For the time being, the dynamic linker falls back to looking up a 'main' function if no 'Component::construct' function could be found. The libc provides an implementation of 'Component::construct', which sets up the libc's task handling and finally call the function 'Libc::Component::construct' from the context of the appllication task. This function is expected to be provided by the libc-using application. Consequently, Genode components that use the libc have to implement the 'Libc::Component::construct' function. The new 'posix' library provides an implementation of 'Libc::Component::construct' that calls a main function. Hence, POSIX programs that merely use the POSIX API merely have to add 'posix' to the 'LIBS' declaration in their 'target.mk' file. Their execution starts at 'main'. Issue #2199 2016-12-22 14:01:19 +00:00			`SRC_CC = construct.cc`

			`LIBS += libc`

Turn posix lib into shared library By building the posix library as shared object with an ABI, we effectively decouple posix-using programs from the library implementation (which happens to depend on several os-level APIs such as the VFS). 2017-05-14 19:55:57 +00:00			`SHARED_LIB = yes`

Simpify startup of dynamically linked binaries This patch removes the component_entry_point library, which used to proved a hook for the libc to intercept the call of the 'Component::construct' function. The mechansim has several shortcomings (see the discussion in the associated issue) and was complex. So we eventually discarded the approach in favor of the explicit handling of the startup. A regular Genode component provides a 'Component::construct' function, which is determined by the dynamic linker via a symbol lookup. For the time being, the dynamic linker falls back to looking up a 'main' function if no 'Component::construct' function could be found. The libc provides an implementation of 'Component::construct', which sets up the libc's task handling and finally call the function 'Libc::Component::construct' from the context of the appllication task. This function is expected to be provided by the libc-using application. Consequently, Genode components that use the libc have to implement the 'Libc::Component::construct' function. The new 'posix' library provides an implementation of 'Libc::Component::construct' that calls a main function. Hence, POSIX programs that merely use the POSIX API merely have to add 'posix' to the 'LIBS' declaration in their 'target.mk' file. Their execution starts at 'main'. Issue #2199 2016-12-22 14:01:19 +00:00			`vpath construct.cc $(REP_DIR)/src/lib/posix`