Build configuration

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Many features in the Lely core libraries can be disabled at compile time by specifying flags to the configure script of the autotools build system or defining the corresponding preprocessor macros.

Language support

C

Most C functions use assert() to validate their input. If you wish to disable assertions, define the NDEBUG preprocessor macro.

Since C11, struct timespec is defined in <time.h>. When using a C99 compiler, the C11 and POSIX compatibility library (liblely-libc) defined this struct in <lely/libc/time.h>. However, some C standard libraries (such as Newlib) define this struct without properly advertising it, leading to a compilation error. Define __timespec_defined to suppress the definition in <lely/libc/time.h>.

Some functions in the Lely core libraries use variable-length arrays (VLAs) on platforms that support it. To prevent stack overflows, VLAs are only used if the size (in bytes) of the resulting array does not exceed a maximum value, given by the LELY_VLA_SIZE_MAX preprocessor macro (default: 256).

C++

Although the Lely core libraries are written in C, C++ interfaces are provided for a subset of the functionality. These interfaces can be disabled with the --disable-cxx option to configure or by defining the LELY_NO_CXX preprocessor macro. This also disables the entire C++ CANopen application library.

Python

The (Cython-generated) Python bindings can be disabled by specifying the --disable-cython option to configure.

The Python tools can be disabled with the --disable-python option. This also disables the Python bindings.

Platform support

Multithreading support can be disabled by providing the --disable-threads option to configure or by defining the LELY_NO_THREADS preprocessor macro.

Support for errno and <errno.h> can be disabled with the --disable-errno option to configure or by defining the LELY_NO_ERRNO preprocessor macro. This option also disables C++ support, since the C++ APIs rely on errno for exception handling.

Support for dynamic memory allocation can be disabled by specifying the --disable-malloc to configure or by defining the LELY_NO_MALLOC preprocessor macro. This option also disables C++ support.

Note: LELY_NO_MALLOC support is preliminary and will not yet disable all dynamic memory allocation.

Support for standard I/O functions (<stdio.h>) can be disabled with the --disable-stdio option to configure or by defining the LELY_NO_STDIO preprocessor macro. It is automatically disabled when support for errno or dynamic memory allocation is disabled.

On POSIX and Windows platforms, the utilities library (liblely-util) provides functions to run a process in the background as a daemon/service. This functionality can be disabled with the --disable-daemon option to configure or by defining the LELY_NO_DAEMON preprocessor macro. Daemon support is automatically disabled when standard I/O support is disabled.

Support for diagnostic functions can be disabled with the --disable-diag option to configure or by defining the LELY_NO_DIAG preprocessor macro. The diagnostic functions can still be used but will have no effect.

The I/O library (liblely-io2) provides a generic CAN message type suitable for both CAN and CAN FD frames. If CAN FD support is not required, the message size can be reduced by specifying the --disable-canfd option to configure or by defining the LELY_NO_CANFD preprocessor macro.

Note: If LELY_NO_CANFD is defined when compiling the libraries, it must also be defined when compiling applications using the can_msg struct.

Windows

If the WINVER, _WIN32_WINNT or NTDDI_VERSION preprocessor macros are not defined, <lely/features.h> (which is included by every header in the Lely core libraries) defines them to 0x0601 (Windows 7, the minimum supported version).

<lely/features.h> also defines WIN32_LEAN_AND_MEAN, if not yet defined, before including <windef.h>.

POSIX

POSIX compatibility, and the availability of optional features, is checked by inspecting the values of the following preprocessor macros:

  • _POSIX_C_SOURCE: used to check if the target platform is POSIX compatible.
  • _POSIX_MAPPED_FILES: used to check for the availability of mmap() (from <sys/mman.h>).
  • _POSIX_PRIORITY_SCHEDULING: used to check for the availability of sched_yield() (from <sched.h>) in the implementation of thrd_yield().
  • _POSIX_THREADS: used to check for the availability of POSIX threads (and <pthread.h>).
  • _POSIX_TIMERS: used to check for the availability of clock_getres(), clock_gettime(), clock_nanosleep(), clock_settime() and nanosleep() in <time.h>.

Event library

The run functions of polling event loop (defined in <lely/ev/loop.h>) require an internal context (which is used, among other things, to wake up an event loop from another thread). To minimize the overhead of allocating these contexts, they are cached and reused, up to a maximum of LELY_EV_LOOP_CTX_MAX_UNUSED (default: 16) unused contexts per event loop.

Support for multiple contexts is necessary because the polling event loop supports nested run functions, i.e., calling a run function from a task that is being executed by another run function.

The fiber executor runs every task in a coroutine. To minimize the overhead of creating coroutines (and allocating their stack), terminated coroutines are cached and reused, up to a maximum of LELY_EV_FIBER_MAX_UNUSED (default: 16) unused coroutines per thread.

CANopen library

If the NDEBUG preprocessor macro is not defined, the CANopen library defines an internal trace() macro that is used to print debug information.

Features

Much of the functionality of CANopen is optional and can be disabled to save space on embedded devices. The CANopen library (liblely-co) supports the following configure options (or preprocessor macros) to disable certain features:

  • --disable-dcf (LELY_NO_CO_DCF): disable EDS/DCF support (also disables the CANopen control tool, CANopen cat server and DCF-to-C tool). EDS/DCF support is automatically disabled when standard I/O support is disabled.
  • --disable-dcf-restore (LELY_NO_CO_DCF_RESTORE): do not (re)store concise DCF of the application parameters.
  • --disable-obj-default (LELY_NO_CO_OBJ_DEFAULT): disable default values in the object dictionary.
  • --disable-obj-file (LELY_NO_CO_OBJ_FILE): disable UploadFile/DownloadFile support for the object dictionary (automatically disabled when standard I/O support is disabled).
  • --disable-obj-limits (LELY_NO_CO_OBJ_LIMITS): disable minimum/maximum values in the object dictionary.
  • --disable-obj-name (LELY_NO_CO_OBJ_NAME): disable names in the object dictionary.
  • --disable-obj-upload (LELY_NO_CO_OBJ_UPLOAD): disable custom upload indication functions in the object dictionary.
  • --disable-sdev (LELY_NO_CO_SDEV): disable static device description support (also disables the DCF-to-C tool).
  • --disable-csdo (LELY_NO_CO_CSDO): disable Client-SDO support (also disables master support).
  • --disable-rpdo (LELY_NO_CO_RPDO): disable Receive-PDO support.
  • --disable-tpdo (LELY_NO_CO_TPDO): disable Transmit-PDO support (also disables the CANopen cat server).
  • --disable-mpdo (LELY_NO_CO_MPDO): disable Multiplex PDO support.
  • --disable-sync (LELY_NO_CO_SYNC): disable synchronization (SYNC) object support.
  • --disable-time (LELY_NO_CO_TIME): disable time stamp (TIME) object support.
  • --disable-emcy (LELY_NO_CO_EMCY): disable emergency (EMCY) object support.
  • --disable-lss (LELY_NO_CO_LSS): disable Layer Setting Services (LSS) and protocols support.
  • --disable-wtm (LELY_NO_CO_WTM): disable Wireless Transmission Media (WTM) support (also disables the CAN-to-UDP tool).
  • --disable-master (LELY_NO_CO_MASTER): disable master support (also disables NMT boot slave and NMT configuration request support).
  • --disable-ng (LELY_NO_CO_NG): disable node guarding support.
  • --disable-nmt-boot (LELY_NO_CO_NMT_BOOT): disable NMT boot slave support (automatically disabled when master support is disabled).
  • --disable-nmt-cfg (LELY_NO_CO_NMT_CFG): disable NMT configuration request support (automatically disabled when master support is disabled).
  • --disable-gw (LELY_NO_CO_GW): disable gateway support (also disables ASCII gateway support).
  • --disable-gw-txt (LELY_NO_CO_GW_TXT): disable ASCII gateway support (also disables the CANopen control tool). ASCII gateway support is automatically disabled when standard I/O support is disabled.

Timeouts

The following preprocessor macros can be defined to change the default timeouts used by an NMT master when booting a slave:

  • LELY_CO_NMT_TIMEOUT: the default timeout (in milliseconds) for SDO requests issued by an NMT master (default: 100). The actual timeout can be changed at runtime with co_nmt_set_timeout().
  • LELY_CO_NMT_BOOT_WAIT_TIMEOUT: the timeout (in milliseconds) before an NMT master tries to boot a slave on error status B (default: 1000, see Fig. 4 in CiA 302-2 version 4.1.0).
  • LELY_CO_NMT_BOOT_SDO_RETRY: the number of times an NMT master retries an SDO request on timeout (default: 3). This is used for SDO requests that may occur right after a slave receives a reset node or reset communication command, which might cause it to miss the request.
  • LELY_CO_NMT_BOOT_RTR_TIMEOUT: the timeout (in milliseconds) after an NMT master sends a node guarding RTR to check the NMT state of a slave during booting (default: 100, see Fig. 9 in CiA 302-2 version 4.1.0).
  • LELY_CO_NMT_BOOT_RESET_TIMEOUT: the timeout (in milliseconds) when waiting for a boot-up message after sending an NMT ‘reset communication’ command (default: 1000).
  • LELY_CO_NMT_BOOT_CHECK_TIMEOUT: the time (in milliseconds) between successive checks of the flash status indication (1F57:01) or program control (1F51:01) sub-object of a slave during booting (default: 100, see Fig. 3 in CiA 302-3 version 4.1.0).
  • LELY_CO_NMT_CFG_RESET_TIMEOUT: the timeout (in milliseconds) after an NMT master sends a ‘reset communication’ or ‘reset node’ command when it has restored the default parameters using object 1011 on the slave. (default: 1000, see Fig. 8 in CiA 302-2 version 4.1.0).

The following macros can be defined to change the default timeouts used by an LSS master:

  • LELY_CO_LSS_INHIBIT: the default inhibit time (in multiples of 100 microseconds) between successive CAN frames sent by an LSS master service (default: 10, which corresponds to 1 ms). The actual timeout can be changed at runtime with co_lss_set_inhibit().
  • LELY_CO_LSS_TIMEOUT: the default timeout (in milliseconds) when waiting for slaves to respond to an LSS request (default: 100). The actual timeout can be changed at runtime with co_lss_set_timeout().

Memory usage

In the absence of dynamic memory allocation (LELY_NO_MALLOC is defined), the following preprocessor macros can be used to change the default size of static arrays and buffers:

  • CO_CSDO_MEMBUF_SIZE: the size (in bytes) of a Client-SDO memory buffer (default: 8). The default size is large enough to accomodate all basic data types.
  • CO_SSDO_MEMBUF_SIZE: the size (in bytes) of a Server-SDO memory buffer (default: 889). The default size is large enough to accomodate the maximum block size used by SDO block transfer.
  • CO_EMCY_CAN_BUF_SIZE: the size (in CAN frames) of an EMCY CAN frame buffer (default: 16).
  • CO_EMCY_MAX_NMSG: the maximum number of active EMCY messages (default: 8).
  • CO_NMT_CAN_BUF_SIZE: the size (in CAN frames) of an NMT CAN frame buffer (default: 16).
  • CO_NMT_MAX_NHB: the maximum number of heartbeat consumers (default: 127). The default value equals the maximum number of CANopen nodes.

C++ CANopen application library

Master and/or slave support for the C++ CANopen application library (liblely-coapp) can be disabled with the following configure options (or preprocessor macros):

  • --disable-coapp-master (LELY_NO_COAPP_MASTER): disable C++ CANopen application master support.
  • --disable-coapp-slave (LELY_NO_COAPP_SLAVE): disable C++ CANopen application slave support.

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