This chapter describes certain characteristics of the GNU Fortran compiler, that are not specified by the Fortran standard, but which might in some way or another become visible to the programmer.

• KIND Type Parameters
• Internal representation of LOGICAL variables
• Evaluation of logical expressions
• MAX and MIN intrinsics with REAL NaN arguments
• Thread-safety of the runtime library
• Data consistency and durability
• Files opened without an explicit ACTION= specifier
• File operations on symbolic links
• File format of unformatted sequential files
• Asynchronous I/O
• Behavior on integer overflow