Argox PA-20 Programming Guide Bedienungsanleitung PDF herunterladen (Seite 46)

PT-20 Programming Guide

readln

Purpose：

Read a line terminated by a null character “\0” from a DAT file.

Syntax：

int readln(int fd, char *buffer, unsigned max_count);

Example call：

readln(fd, buffer, 50);

Includes：

#include “SDK.h ”

Description：

The readln function reads a line from the DAT file whose file

handle is fd and stores the characters in the character array buffer.

Characters are read until end-of-file encountered, a null character

(\0) encountered, or the total number of characters read equals the

number specified in max_count. The readln function then returns

the number of bytes actually read from the file. The null character

(\0) is also counted if read. If the readln function completes its

operation not because a null character is read, there will be no null

character stored in buffer. Reading starts at the current position of

the file pointer, which is incremented accordingly when the

operation is completed.

Returns：

The readln function returns the number of bytes actually read

from the file (includes the null character if read). In case of error,

readln returns an integer value of -1 and an error code is set to the global

variable fErrorCode to indicate the error condition

encountered. Possible error codes and their interpretation are

listed below.

fErrorCode：

2:File handle is NULL.

7:fd is not a file handle of a previously opened file.

_remove

Purpose：

Delete file.

Syntax：

int _remove(char *filename);

Example call：

if (_remove(C:\\data\\store.dat) _puts(“store.dat deleted”);

Includes：

#include “SDK.h ”

Description：

Delete the file specified by filename. If filename exceeds 8

characters, it will be truncated to 8 characters long. If the file to be

deleted is a DBF file, the DBF file and all the index (key)

files associated to it will be deleted altogether.

Returns：

If remove deletes the file successfully, it returns an integer value

of 1. In case of error, remove will return an integer value of 0 and

an error code is set to the global variable fErrorCode to indicate

the error condition encountered. Possible error codes and their

interpretations are listed below.

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