Specifies the default calling convention and argument-passing convention for an application.
IDE Equivalent
Windows: External Procedures > Calling Convention (/iface:{cref|stdref|stdcall|cvf|default})
External Procedures > String Length Argument Passing (/iface:[no]mixed_str_len_arg)
Linux: None
Mac OS X: None
Architectures
IA-32, Intel® 64 architectures
Syntax
Linux and Mac OS X: | None |
Windows: | /iface:keyword |
Arguments
keyword |
Specifies the calling convention or the argument-passing convention. Possible values are:
|
Default
/iface:default |
The default calling convention is used. |
Description
This option specifies the default calling convention and argument-passing convention for an application.
The aspects of calling and argument passing controlled by this option are as follows:
The calling mechanism (C or STDCALL): On IA-32 architecture, these mechanisms differ in how the stack register is adjusted when a procedure call returns. On Intel® 64 architecture, the only calling mechanism available is C; requests for the STDCALL mechanism are ignored.
The argument passing mechanism (by value or by reference)
Character-length argument passing (at the end of the argument list or after the argument address)
The case of external names (uppercase or lowercase)
The name decoration (prefix and suffix)
You can also use the ATTRIBUTES compiler directive to modify these conventions on an individual basis. Note that the effects of the ATTRIBUTES directive do not always match that of the iface option of the same name.
Option |
Description |
|---|---|
/iface:default |
Tells the compiler to use the default calling conventions. These conventions are as follows:
|
/iface:cref |
Tells the compiler to use the same conventions as /iface:default except that external names are lowercase. |
/iface:cvf |
Tells the compiler to use calling conventions compatible with Compaq Visual Fortran* and Microsoft Fortran PowerStation. These conventions are as follows:
|
/iface:mixed_str_len_arg |
Specifies argument-passing conventions for hidden-length character arguments. This option tells the compiler that the hidden length passed for a character argument is to be placed immediately after its corresponding character argument in the argument list. This is the method used by Compaq Visual Fortran*. When porting mixed-language programs that pass character arguments, either this option must be specified correctly or the order of hidden length arguments must be changed in the source code. This option can be used in addition to other /iface options. |
/iface:stdcall |
Tells the compiler to use the following conventions:
|
/iface:stdref |
Tells the compiler to use the same conventions as /iface:stdcall except that argument passing is by reference. |
Caution
On Windows systems, if you specify option /iface:cref, it overrides the default for external names and causes them to be lowercase. It is as if you specified "!dec$ attributes c, reference" for the external name.
If you specify option /iface:cref and want external names to be uppercase, you must explicitly specify option /names:uppercase.
Caution
On systems using IA-32 architecture, there must be agreement between the calling program and the called procedure as to which calling mechanism (C or STDCALL) is used or unpredictable errors may occur. If you change the default mechanism to STDCALL, you must use the ATTRIBUTES DEFAULT directive to reset the calling conventions for routines specified with the USEROPEN keyword in an OPEN statement and for comparison routines passed to the QSORT library routine.
Alternate Options
/iface:cvf |
Linux and Mac OS X: None Windows: /Gm |
/iface:mixed_str_len_arg |
Linux and Mac OS X: -mixed-str-len-arg Windows: None |
/iface:nomixed_str_len_arg |
Linux and Mac OS X: -nomixed-str-len-arg Windows: None |
/iface:stdcall |
Linux and Mac OS X: None Windows: /Gz |