# FreeRTOS MBEDlpc1768 Keil offline Compiler

**URL:** <https://forums.freertos.org/t/freertos-mbedlpc1768-keil-offline-compiler/2637>\
**Category:** Kernel\
**Created:** [September 28, 2011, 6:21am UTC](https://forums.freertos.org/t/freertos-mbedlpc1768-keil-offline-compiler/2637 "2011-09-28T06:21:24Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![system](https://d2v6vdsk2p900z.cloudfront.net/original/1X/7fc8fdb729c645aab5b20282bbe34e57cb407be6.jpeg) [@system](https://forums.freertos.org/u/system)\
**Post date:** [September 28, 2011, 6:21am UTC](https://forums.freertos.org/t/freertos-mbedlpc1768-keil-offline-compiler/2637/1 "2011-09-28T06:21:24Z")

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**[sbir85](https://sourceforge.net/u/sbir85/)** wrote on [Wednesday, September 28, 2011](https://sourceforge.net/p/freertos/discussion/382005/thread/7429f694/#0f2c):

Hi,  
I implement the FreeRTOS in my uVision project, but I got a Linker problem.  
I’m not sure what’s the problem:

Error: L6218E: Undefined symbol vTaskStartScheduler  
(referred from main.o).

Do you have a sample of FreeRTOS for Keil for LPC1768 or LPC17xx ?  
in the Sample list is just a sample for Eclipse.

Thanks for your help

best regards

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**Author:** ![rtel](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/rtel/32/31_2.png) [@rtel](https://forums.freertos.org/u/rtel)\
**Post date:** [September 28, 2011, 9:18am UTC](https://forums.freertos.org/t/freertos-mbedlpc1768-keil-offline-compiler/2637/2 "2011-09-28T09:18:18Z")

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**[rtel](https://sourceforge.net/u/rtel/)** wrote on [Wednesday, September 28, 2011](https://sourceforge.net/p/freertos/discussion/382005/thread/7429f694/#e5aa):

vTaskStartScheduler() is defined in tasks.c, so the first thing to do is ensure that tasks.c is included in the build.&nbsp; I assume it is, so the next question would be, how is it being build?&nbsp; The MBED code is C++, which means, and to call C code you must do two things - first ensure that tasks.c is being built as C and not C++, and second ensure that the function is declared extern “C”.&nbsp; The FreeRTOS header files take care of the second part of that already.

You could alternatively build the FreeRTOS code as C++, but that would involve removing some of the data hiding it employs (i.e. changing the code).&nbsp; There are lots of threads about on this topic, and it is a bit outside of my core knowledge.

Regards.