well ,as per my knowledge (though u need to confirm that from seniors) ,if u came here on study permit ,and an employer wants to offer a job to you, then if u wanna go for that job u'll have to surrender the study permit in order to get the work permit (this work permit is different than what most of the international students might know),u have to get the LMO (Labour market opinion through HRSDC) ,once granted ok ,u r good to go and after 2 years of experience u can apply for CEC.
P.S you'll have to renew your permit every now and then ,so its important u do have the job and the employer who can support you in this process.
** i am not an expert ,just read blogs and spent two years here in Canada and spent 30K on studies and still spending more

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