Filenames (Debugging with GDB)
From Get docs
Gdb/docs/latest/gdb/Filenames
15.1.1 List of Filename Extensions and Languages
If a source file name ends in one of the following extensions, then GDB infers that its language is the one indicated.
.ada
.ads
.adb
.a
- Ada source file.
.c
- C source file
.C
.cc
.cp
.cpp
.cxx
.c++
- C++ source file
.d
- D source file
.m
- Objective-C source file
.f
.F
- Fortran source file
.mod
- Modula-2 source file
.s
.S
- Assembler source file. This actually behaves almost like C, but GDB does not skip over function prologues when stepping.
In addition, you may set the language associated with a filename extension. See Displaying the Language.