/in/foo.c:1:1: error: unknown type name 'def'
    1 | def calculate_triangle_perimeter(a, b, c):
      | ^~~
/in/foo.c: In function 'calculate_triangle_perimeter':
/in/foo.c:1:42: error: expected declaration specifiers before ':' token
    1 | def calculate_triangle_perimeter(a, b, c):
      |                                          ^
/in/foo.c:1:5: warning: type of 'a' defaults to 'int' [-Wimplicit-int]
    1 | def calculate_triangle_perimeter(a, b, c):
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/in/foo.c:1:5: warning: type of 'b' defaults to 'int' [-Wimplicit-int]
/in/foo.c:1:5: warning: type of 'c' defaults to 'int' [-Wimplicit-int]
/in/foo.c:6: warning: control reaches end of non-void function [-Wreturn-type]