08-19-2008
It's been a long time, but if I recall it works like this....
Each serial port has a port-buffer (in the old days this could be as little as 8 bytes) and you process buffer traffic 1 character at a time. I don't know what higher-level abstractions are provided these days for processing the bytes in the buffer, but the basic idea remains the same....
While (forever){
if (character-at-buffer-1){
read it;
do something with it;
}
if (character-at-buffer-2){
read it;
do something with it;
}
do other stuff here, but never so much that at 9600 cps the buffer(s)
could over-flow
}
For example, a simple terminal emulator comes down to this...
Open handle SR to read serial buffer;
Open handle SW to write serial buffer;
Open handle KR to read keyboard press;
Open handle TW to write to terminal;
while (forever){
if (SR has char){
write to TW;
}
if (KR has char){
write to SW;
}
Do other stuff;
}
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LEARN ABOUT DEBIAN
caca_file_tell
libcaca file IO(3caca) libcaca libcaca file IO(3caca)
NAME
libcaca file IO -
Functions
__extern caca_file_t * caca_file_open (char const *, const char *)
Open a file for reading or writing.
__extern int caca_file_close (caca_file_t *)
Close a file handle.
__extern uint64_t caca_file_tell (caca_file_t *)
Return the position in a file handle.
__extern size_t caca_file_read (caca_file_t *, void *, size_t)
Read data from a file handle.
__extern size_t caca_file_write (caca_file_t *, const void *, size_t)
Write data to a file handle.
__extern char * caca_file_gets (caca_file_t *, char *, int)
Read a line from a file handle.
__extern int caca_file_eof (caca_file_t *)
Tell whether a file handle reached end of file.
Detailed Description
These functions allow to read and write files in a platform-independent way.
Function Documentation
__extern caca_file_t* caca_file_open (char const *path, const char *mode) Create a caca file handle for a file. If the file is zipped, it is
decompressed on the fly.
If an error occurs, NULL is returned and errno is set accordingly:
o ENOSTS Function not implemented.
o EINVAL File not found or permission denied.
Parameters:
path The file path
mode The file open mode
Returns:
A file handle to path.
Referenced by caca_import_canvas_from_file().
__extern int caca_file_close (caca_file_t *fp) Close and destroy the resources associated with a caca file handle.
This function is a wrapper for fclose() or, if available, gzclose().
Parameters:
fp The file handle
Returns:
The return value of fclose() or gzclose().
Referenced by caca_import_canvas_from_file().
__extern uint64_t caca_file_tell (caca_file_t *fp) Return the file handle position, in bytes.
Parameters:
fp The file handle
Returns:
The current offset in the file handle.
__extern size_t caca_file_read (caca_file_t *fp, void *ptr, size_tsize) Read data from a file handle and copy them into the given buffer.
Parameters:
fp The file handle
ptr The destination buffer
size The number of bytes to read
Returns:
The number of bytes read
Referenced by caca_import_canvas_from_file().
__extern size_t caca_file_write (caca_file_t *fp, const void *ptr, size_tsize) Write the contents of the given buffer to the file handle.
Parameters:
fp The file handle
ptr The source buffer
size The number of bytes to write
Returns:
The number of bytes written
__extern char* caca_file_gets (caca_file_t *fp, char *s, intsize) Read one line of data from a file handle, up to one less than the given
number of bytes. A trailing zero is appended to the data.
Parameters:
fp The file handle
s The destination buffer
size The maximum number of bytes to read
Returns:
The number of bytes read, including the trailing zero
__extern int caca_file_eof (caca_file_t *fp) Return the end-of-file status of the file handle.
This function is a wrapper for feof() or, if available, gzeof().
Parameters:
fp The file handle
Returns:
1 if EOF was reached, 0 otherwise
Referenced by caca_import_canvas_from_file().
Author
Generated automatically by Doxygen for libcaca from the source code.
Version 0.99.beta18 Fri Apr 6 2012 libcaca file IO(3caca)