Issues so that debugging always involves using the names as they appear In future versions of GNU Fortran we hope to improve naming and linking Underscores introduces the very real possibility that a user-definedĮxternal name will conflict with a name in a system library, whichĬould make finding unresolved-reference bugs quite difficult in someĬases-they might occur at program run time, and show up only as Significant effort, and, unlike naming disagreements, linkers normallyĬannot detect disagreements in these other areas.Īlso, note that with -fno-underscoring, the lack of appended
#Simply fortran no source detected code#
Small part of the overall solution-getting the code generated byīoth compilers to agree on issues other than naming can require
That is, getting code produced by GNU Fortran to link to code producedīy some other compiler using this or any other method can be only a Interface implemented by some other language for that same name. Interface implemented by GNU Fortran for an external name matches the Note that just because the names match does not mean that the User-defined names while debugging and when interfacing GNU Fortran Use of -fno-underscoring allows direct specification of With -fno-underscoring, the same statement is implemented as: fcase-lower and that j() and max_count() areĮxternal functions while my_var and lvar are local variables, Use of -fno-underscoring is not recommended unless you areĮxperimenting with issues such as integration of GNU Fortran intoĮxisting system environments (vis-à-vis existing libraries, tools,įor example, with -funderscoring, and assuming other defaults like GNU Fortran to be compatible with object code created with these ff2c option if you want object files compiled with Incompatible with f2c and g77, please use the This is done to ensureĬompatibility with code produced by many UNIX Fortran compilers.Ĭaution: The default behavior of GNU Fortran is Underscore to external names with no underscores. With -funderscoring in effect, GNU Fortran appends one Source file by appending underscores to them. fno-underscoring Do not transform names of entities specified in the Fortran The library implementations use the -fno-f2c calling conventions. Of type default REAL or COMPLEX as actual arguments, as ff2c with code compiled with the default -fno-f2cĬalling conventions as, calling COMPLEX or default REALįunctions between program parts which were compiled with differentĬalling conventions will break at execution time.Ĭaution: This will break code which passes intrinsic functions This does not affect the generation of code that interfaces withĬaution: It is not a good idea to mix Fortran code compiled with Option, unless -fno-second-underscore is explicitly requested. Under the default GNU calling conventions, suchįunctions simply return their results as they would in GNUĬ-default REAL functions return the C type float, andĬOMPLEX functions return the GNU C type complex.Īdditionally, this option implies the -fsecond-underscore In f2c) require functions that return typeĭefault REAL to actually return the C type double, andįunctions that return type COMPLEX to return the values via anĮxtra argument in the calling sequence that points to where to The calling conventions used by g77 (originally implemented ff2c Generate code designed to be compatible with code generated Use the option -frecursive to use no static memory. Variables smaller than the value given by -fmax-stack-var-size.
The default, which is -fautomatic, uses the stack for local Provide this option under the name -static or -save.) SAVE statement were specified for every local variable and array fno-automatic Treat each program unit (except those marked as RECURSIVE) as if the
YouĬan figure out the other form by either removing no- or adding One of the forms is listed-the one which is not the default. Most of them have both positive and negative forms the negative form These machine-independent options control the interface conventions 2.9 Options for code generation conventions