gdb-thread-number

gdb-thread-number is a variable defined in `gdb-mi.el'.
Its value is

nil

Documentation:
Main current thread.

Invalidation triggers use this variable to query GDB for
information on the specified thread by wrapping GDB/MI commands
in `gdb-current-context-command'.

This variable may be updated implicitly by GDB via `gdb-stopped'
or explicitly by `gdb-select-thread'.

Only `gdb-setq-thread-number' should be used to change this
value.