Metrologic Optimus R, Руководство по программированию

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Chapter 3 Terminal Specific Function Library 197
See Also lseek
write
Purpose To write a specified number of bytes to a DAT file.
Syntax int write (int fd, char *buffer, int count);
int fd; /* file handle of the target DAT file */
char *buffer; /* pointer to a buffer where data is written to */
int count; /* number of bytes to be written */
Example write (fd, data_buffer, 1024);
Description This routine writes a number of bytes (
count
) from the character array
buffer
to
a DAT file (
fd
).
Writing of data starts at the current file pointer position, which is
incremented accordingly when the operation is completed.
If end-of-file is encountered during operation, this routine will
automatically extend the file size to hold the data written.
The maximum number of characters that can be written is 32767.
Return If successful, it returns the number of bytes actually written to the file.
On error, it returns -1.
An error code is set to the global variable fErrorCode to indicate the error
condition encountered. Below are possible error codes and their interpretation.
Error Code Interpretation
2 File specified by fd does not exist.
4 File specified by fd is not a DAT file.
7 Invalid file handle.
8 File not opened.
9 The value of
count
is negative.
10 No free file space for file extension.
See Also append, appendln, read, readln, writeln
writeln
Purpose
To write a line (null-terminated string) to a DAT file.
Syntax int writeln (int fd, char *buffer);
int fd; /* file handle of the target DAT file */
char *buffer; /* pointer to a buffer where data is written to */