73 lines
1.6 KiB
C
73 lines
1.6 KiB
C
/*
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* This is an encapsulation of a National Instruments counter.
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*
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* It presents a simple 64-bit counter abstraction. When the counter is
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* created, it commences counting at zero until it is destroyed.
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*
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* The counter can be read and returns a 64-bit unsigned value.
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*/
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#ifndef _HCTR_H_
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#define _HCTR_H_
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#include <stdbool.h>
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struct counter_private_t;
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typedef struct counter_private_t* pHCTR;
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/**
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* Create a 64-bit counter and start it counting
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*
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* \param device_name the name of the device (e.g. "dev1/ctr0")
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* \param ptr address of pointer to opaque private data structure
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*
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* \return
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* 0 OK
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* !0 Error
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*/
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int hctr_ctor(const char* device_name, pHCTR* ptr);
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/**
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* Read the value of the 64-bit counter
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*
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* \param hctr pointer to opaque private data structure
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* \param value address of unsigned 64-bit value to receive the output
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*
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* \return
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* 0 OK
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* !0 Error
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*/
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int hctr_read(pHCTR hctr, unsigned long long* value);
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/**
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* Destroy the 64-bit counter
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*
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* \param ptr address of pointer to opaque private data structure
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*
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* \return
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* 0 OK
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* !0 Error
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*/
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int hctr_dtor(pHCTR* hctr);
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/**
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* Tests returned error value to see if it represents failure
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*
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* \param error a value returned from another hctr function
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*
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* \return
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* true the error was a failure
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* false the error was not a failure (warning)
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*/
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bool hctr_failed(int error);
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/**
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* Retrieves a textual representation of the most recent error
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*
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* \param buff a pointer to the buffer to receive the text
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* \param len the length of the provided buffer
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*/
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void hctr_errmsg(char* buff, int len);
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#endif
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