[GitHub] [incubator-nuttx] patacongo opened a new pull request #1168: sched/task/task_spawn.c: Fix duplicate task_spawn()

[GitBox <gi...@apache.org>]

patacongo opened a new pull request #1168:
URL: https://github.com/apache/incubator-nuttx/pull/1168


   ## Summary
   
   In the FLAT build if CONFIG_LIB_SYSCALL=y, then the function task_spawn() will be duplicated.:  One version in libs/libc/spawn and one version in sched/task.
   
   The version of task_spawn in lib/libc/spawn exists only if CONFIG_LIB_SYSCALL is selected.  In that case, the one in sched/task/task_spawn.c should be static, at least in the FLAT build.
   
   The version of task_spawn.c in libs/libc/spawn simply marshals the parameters into a structure and calls nx_task_spawn().  If CONFIG_LIB_SYSCALL is defined then nx_task_spawn() will un-marshal the data can call the real task spawn.  This nonsense is only necessary because task_spawn has 8 parameters and the maximum number of parameters in a system call is only 6.
   
   Without syscalls:  Application should call directly in task_spawn() in sched/task/task_spawn.c and, hence, it must not be static
   
   With syscalls:  Application should call the marshalling task_spawn() in libs/libc/spawn/lib_task_spawn.c -> That will call the autogenerated nx_task_spawn() proxy -> And generate a system call -> The system call will the unmarshalling nx_task_spawn() in sched/task/task_spawn.c -> Which will, finally, call the real task_spawn().
   
   The side-effect of making task_spawn() static is that it then cannot be used within the OS.  But as far as I can tell, nothing in the OS itself currently uses task_spawn() so I think it is safe to make it conditionally static.  But that only protects from duplicate symbols in the useless case mentioned above.
   


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[GitHub] [incubator-nuttx] Ouss4 merged pull request #1168: sched/task/task_spawn.c: Fix duplicate task_spawn()

[GitBox <gi...@apache.org>]

Ouss4 merged pull request #1168:
URL: https://github.com/apache/incubator-nuttx/pull/1168


   


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