This option only has meaning when generating an XML schema definitions (XSD) file using the -xsd option.

It instructs the compiler to generate an XSD application information section (<appinfo>) for certain ASN.1-only items. The items are specified as a comma-delimited list. Valid values for items are tags, enum, and ext.

<items> is an optional parameter. If it is not specified, it is assumed that application information should be produced for all three item classes: ASN.1 tags, ASN.1 enumerations, and extended elements.

This option specifies that an array type will be used for SEQUENCE OF/SET OF constructs.

This option specifies the default size of static array variables. This will be overridden by the value of a SIZE constraint on the given type, if it exists.

This option only has meaning when generating an XML schema definitions (XSD) file using the -xsd option.

It instructs the compiler to generate non-native attributes for certain ASN.1-only items that cannot be expressed in XSD. The items are specified as a comma-delimited list. Valid values for items are tags, enum, and ext.

<items> is an optional parameter. If it is not specified, it is assumed that application information should be produced for all three item classes: ASN.1 tags, ASN.1 enumerations, and extended elements.

This option causes a simple client sample program to be generated that will connect to a server, encode and send a message, and then wait for a response. Once the response is received, it will be printed and the program will terminate.

The template code that is used for the server is located in the server.cpp in the templates directory and may be modified to produce different behavior.

Note that as of this release, only C++ client programs are supported.

Generate code compatible with an older version of ASN1C. The compiler will attempt to generate code more closely aligned with the given previous release of the compiler.

<versionNumber> is specified as x.x (for example, -compat 5.2)

This option specifies that a dynamic array type is to be used for SEQUENCE OF/SET OF constructs.

The -fqenum (fully-qualified enum) option may be used to make C names unique. When specified, enumerated identifiers will be automatically prefixed with the enclosing type name. This can be useful in situations where common identifiers are often repeated in different types. This is not a problem in C++ because the identifiers are wrapped in a struct declaration which provides a namespace for the values.

This option allows the specification of a C or C++ source (.c or .cpp) file to which generated compare functions will be written. Compare functions allow two variables of a given ASN.1 type to be compared for equality.

The <filename> argument to this option is optional. If not specified, the functions will be written to <modulename>Compare.c where <modulename> is the name of the module from the ASN.1 source file.

This option allows the specification of a C or C++ source (.c or .cpp) file to which generated copy functions will be written. Copy functions allow a copy to be made of an ASN1C generated variable. For C++, they cause copy constructors and assignment operators to be added to generated classes.

The <filename> argument to this option is optional. If not specified, the functions will be written to <modulename>Copy.c where <modulename> is the name of the module from the ASN.1 source file.

This option instructs the compiler to generate a portable makefile for compiling generated C or C++ code. If used with the -w32 command-line option, a makefile that is compatible with the Microsoft Visual Studio nmake utility is generated; otherwise, a GNU-compatible makefile is generated.

Note that the -nmake option may be used instead of the -make -w32 combination to produce a Visual Studio makefile.

This option allows the specification of a C or C++ source (.c or .cpp) file to which generated print functions will be written. Print functions are debug functions that allow the contents of generated type variables to be written to stdout.

The <filename> argument to this option is optional. If not specified, the print functions will be written to <modulename>Print.c where <modulename> is the name of the module from the ASN.1 source file.

This option allows the specification of a C or C++ source (.c or .cpp) file to which generated "print-to-string" functions will be written. "Print-to-string" functions are similar to print functions except that the output is written to a user-provided text buffer instead of stdout. This makes it possible for the use to display the results on different output devices (for example, in a text window).

The <filename> argument to this option is optional. If not specified, the functions will be written to <modulename>Print.c where <modulename> is the name of the module from the ASN.1 source file.

This option allows the specification of a C or C++ source (.c or .cpp) file to which generated "print-to-stream" functions will be written. "Print-to-stream" functions are similar to print functions except that the output is written to a user-provided stream instead of stdout. The stream is in the form of an output callback function that can be set within the run-time context making it possible to redirect output to any type of device.

The <filename> argument to this option is optional. If not specified, the functions will be written to <modulename>Print.c where <modulename> is the name of the module from the ASN.1 source file.

This option allows the specification of a C or C++ source (.c or .cpp) file to which generated "test" functions will be written. "Test" functions are used to populate an instance of a generated PDU type variable with random test data. This instance can then be used in an encode function call to test the encoder. Another advantage of these functions is that they can act as templates for writing your own population functions.

The <filename> argument to this option is optional. If not specified, the functions will be written to <modulename>Test.c where <modulename> is the name of the module from the ASN.1 source file.

This option specifies that a linked-list type is to be used for SEQUENCE OF/SET OF constructs.

This option is used to specify the maximum number of lines per generated .c or .cpp file. If this number is exceeded, a new file is started with a "_n" suffix where "n" is a sequential number. The default value if not specified is 50,000 lines which will prevent the VC++ "Maximum line numbers exceeded" warning that is common when compiling large ASN.1 source files.

Note that this number is approximate - the next file will not be started until this number is exceeded and the compilation unit that is currently being generated is complete.

This option is used to suppress the generation of initialization functions. A variable of a generated structure can always be initialized by memset’ing the variable to zero. However, this is not usually the most efficient way to initialize a variable because if it contains large byte arrays, a significant amount of processing is required to set all bytes to zero (and they don’t need to be). Initialization functions provide a smart alternative to memset’ing in that only what needs to be set to zero actually is.

Note that previous versions of ASN1C did not generate initialization functions by default. The -genInit switch has been deprecated in favor of -noInit.

This option suppresses the generation of utility functions in C and C++ that assist in converting enumerated values to strings and vice versa. XER and XML encodings are unaffected by this option, since conversions are necessary for encoding and decoding.

This option suppresses the automatic generation of unique names to resolve name clashes in the generated code. Name clashes can occur, for example, if two modules are being compiled that contain a production with the same name. A unique name is generated by prepending the module name to one of the productions to form a name of the form <module>_<name>.

Note that name collisions can also be manually resolved by using the typePrefix, enumPrefix, and valuePrefix configuration items (see the Compiler Configuration File section for more details).

Previous versions of ASN1C did not generate unique names by default. The compiler option -uniquenames has been deprecated in favor of -nouniquenames.

Designate given type name to be a "Protocol Definition Unit" (PDU) type. This will cause a C++ control class to be generated for the given type. By default, PDU types are determined to be types that are not referenced by any other types within a module. This option allows that behavior to be overridden.

The "all" keyword may be specified for <typeName> to indicate that all productions within an ASN.1 module should be treated as PDU types.

This option causes a simple server sample program to be generated. This program will listen for a connection on a given port. When a connection request is received, the connection will be established and the program will read a complete message from the client. It will then send a response to the client and terminate.

The template code that is used for the server is located in the server.cpp in the templates directory and may be modified to produce different behavior.

Note that as of this release, only C++ server programs are supported.

This option is used to generate stream-based encoders/decoders instead of memory buffer based. This makes it possible to encode directly to or decode directly from a source or sink such as a file or socket. In the case of BER, it will also cause forward encoders to be generated which will use indefinite lengths for all constructed elements in a message.

Note that stream and memory-buffer based encode/decode functions cannot be used/combined in any way. The two are mutually exclusive. If the -stream option is selected, then only stream-based run-time functions can be used with the generated code.

This option is used to enable strict checking for conformance to ASN.1 standards and validation of constraints.

This option causes strict interpretation of size constraints to be enabled. This may result in the generation of more optimized code as unnecessary size variable holders are eliminated. For example, a declaration of OCTET STRING (SIZE(10)) will result in the generation of a 10 byte static array rather than a structure with a count field and array.

This option is used to do a syntax check of the ASN.1 source files only. No code is generated.

This option only has meaning when generating an XML schema definitions (XSD) file using the -xsd option.

It allows specification of a target namespace. <namespace> is a namespace URI; if it is not provided, no target namespace declaration is added to the generated XSD file.

This option is used to generate Visual C++- or Visual Studio-compatible project files to compile generated source code. This is a Windows-only option. By passing one of the listed years, the compiler will generate a project that links against libraries provided for those versions of Visual Studio or Visual C++. For example, specifying 2013 will generate a project that links against libraries in the *_vs2013 directory. Not specifying a year will cause the compiler to link against libraries compiled for Visual Studio 2017.

A custom build rule is generated that deletes the generated source files and then invokes ASN1C to regenerate them when a rebuild is done. Doing a clean operation will cause the generated source files to be deleted; a subsequent build will regenerate them.

For Visual C++ 6.0 project files you can see this build rule by locating the first ASN.1 file under the Source Files for the project, right clicking it, choosing Settings... and then choosing the Custom Build tab.

For all other Visual Studio project files the procedure to see the custom rule is very similar to that for Visual C++ 6.0, except that you choose Properties when you right click on the first ASN.1 file, and then click on Custom Build Step or Custom Build Tool on the left.