Argox PA-20 Programming Guide Manuel d'utilisateur télécharger pdf (Page 54)

PT-20 Programming Guide

Creates a file and opens it for both reading and writing.

If file exists, current contents are destroyed.

Returns：

If the file is opened successfully, _fopen returns a pointer to the file. Actually,

this is a pointer to a structure of type _TFILE, which is defined in the header

file. The actual structure is allocated elsewhere and you do not have to

allocate it. In case of an error, _fopen returns a NULL.

_fread

Purpose：

Use _fread to read a specified number of data items, eachof a given size,

from the current position in a file opened for buffered input. The current

position is updated after the read.

Syntax：

size_t _fread(const void *buffer, size_t size, size_t count, _TFILE

*file_pointer);

Example call：

Numread = _fread(buffer, sizeof(char), 80, infile);

Includes：

#include “SDK.h”

Description：

The fread function reads count data items, each of size bytes, starting at the

current read position of the file specified by the argument file_pointer. After

the read is complete, the current position is updated. You must allocate

storage for a buffer to hold the number of bytes that you expect to read. This

buffer is a pointer to a void data type.

Returns：

The _fread function returns the number of items it successfully read.

_fseek

Purpose：

Use _fseek to move to a new position in a file opened for buffered

input/output.

Syntax：

int _fseek(_TFILE *file_pointer, long offset, int origin);

Example call：

_fseek(infile, 0, SEEK_SET); /* Go to the beginning */

Includes：

#include “SDK.h”

Description：

The fseek function sets the current read or write position of the file specified

by the argument file_pointer to a new value indicated by the arguments

“off-set” and “origin”. The

“offset” is a long integer indicating how far away the new position is from a

specific location given in “origin”. The following table explains the possible

value of “origin”.

Origin

Interpretation

SEEK_SET

SEEK_CUR

Beginning of file.

Current position in the file.

Returns：

When successful, _fread returns a zero. In case of error, _fread returns a

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Argox PA-20 Programming Guide Manuel d'utilisateur Page 54

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