Argox PA-20 Programming Guide - Manual (Page 40)

PT-20 Programming Guide 38
Purpose： Write a null terminated character string to the bottom
(end-of-file position) of a DAT file.
Syntax： int appendln(int fd, char *buffer);
Example call： appendln(fd, data_buffer);
Includes： #include “SDK.h ”
Description： The appendln function writes a null terminated character string
from the character array buffer to a DAT file whose file handle is
fd. Characters are written to the file until a null character (\0) is
encountered. The null character is also written to the file. Writing
of data starts at the end-of-file position. The file pointer position
is unaffected by the operation. The appendln function will
automatically extend the file size of the file to hold the data
written.
Returns： The appendln function returns the number of bytes actually
written to the file (includes the null character). In case of error,
appendln 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 specified by fd does not exist.
8:File not opened
10:No more free file space for file extension.
11:Can not find string treminator in buf.
chsize
Purpose： Extends or truncates a DAT file.
Syntax： int chsize(int fd, long new_size);
Example call： if (chsize(fd, 0)) _puts(“file truncated!\n”);
Includes： #include “SDK.h ”
Description： The chsize function truncates or extends the file specified by the
argument fd to match the new file length in bytes given in the
argument new_size. If the file is truncated, all data beyond the
new file size will be lost. If the file is extended, no initial value is
filled to the newly extended area.
Returns： If chsize successfully changes the file size of the specified DAT
file, it returns an integer value of 1. In case of error, chsize 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 interpretation are listed below.