I got two threads (thrd_t): one main thread processing events
and one child thread waiting for terminal input using fgetwc.
#include <threads.h> // mtx_t, mtx_lock, mtx_unlock
#include <wchar.h> // fgetwc, fgetwc_unlocked
FILE* f = (FILE*) p2;
mtx_t* m = (mtx_t*) p1;
volatile sig_atomic_t* i = (volatile sig_atomic_t*) p0;
mtx_lock(m);
volatile wint_t c = fgetwc(f);
if (c != WEOF) {
ungetwc(c, f);
copy_integer(p0, (void*) TRUE_BOOLEAN_STATE_CYBOI_MODEL);
}
mtx_unlock(m);
while (*i != *FALSE_BOOLEAN_STATE_CYBOI_MODEL);
Since I want to read ansi escape code sequences (three characters),
the terminal must not block after each character and is therefore
set to non-blocking in the main thread using t.c_cc[VMIN]=0.
After the sequence has been detected, I reset the terminal to blocking
using t.c_cc[VMIN]=1, so that the child thread blocks at fgetwc
until the next input gets detected.
mtx_t* m = (mtx_t*) p3;
int* i = (int*) p2;
// The loop break flag.
int b = *FALSE_BOOLEAN_STATE_CYBOI_MODEL;
// The escape character flag.
int esc = *FALSE_BOOLEAN_STATE_CYBOI_MODEL;
int aec = *FALSE_BOOLEAN_STATE_CYBOI_MODEL;
// The input character.
wint_t c = WEOF;
mtx_lock(m);
// Set unblocking mode in terminal.
edit_service(p4, (void*) FALSE_BOOLEAN_STATE_CYBOI_MODEL, (void*) FALSE_BOOLEAN_STATE_CYBOI_MODEL, (void*) FALSE_BOOLEAN_STATE_CYBOI_MODEL, (void*) TERMINAL_CYBOI_CHANNEL);
while (*TRUE_BOOLEAN_STATE_CYBOI_MODEL) {
if (b != *FALSE_BOOLEAN_STATE_CYBOI_MODEL) {
break;
}
read_unix_terminal_character(p0, p1, (void*) &b, (void*) &esc, (void*) &aec, (void*) &c);
}
// Set blocking mode in terminal. VMIN = 1
edit_service(p4, (void*) TRUE_BOOLEAN_STATE_CYBOI_MODEL, (void*) FALSE_BOOLEAN_STATE_CYBOI_MODEL, (void*) FALSE_BOOLEAN_STATE_CYBOI_MODEL, (void*) TERMINAL_CYBOI_CHANNEL);
// Reset interrupt request in input/output entry.
copy_integer(i, (void*) FALSE_BOOLEAN_STATE_CYBOI_MODEL);
mtx_unlock(m);
Problem: Sometimes, fgetwc blocks, other times it does not.
When a character sequence was read in (three characters),
the reading loop is left at the third character and
the child thread blocks fine.
When a single character is read, then its end gets detected by a
following WEOF, but the child thread does not block anymore,
even though t.c_cc[VMIN]=1.
wint_t* c = (wint_t*) p5;
int* aec = (int*) p4;
int* esc = (int*) p3;
FILE* f = (FILE*) p1;
*c = fgetwc(f);
if (*c != WEOF) {
if (*aec == *TRUE_BOOLEAN_STATE_CYBOI_MODEL) {
// The character sequence ESC[ was received before.
// This is the beginning of an ansi escape code sequence.
// Reset ansi escape code flag.
copy_integer(p4, (void*) FALSE_BOOLEAN_STATE_CYBOI_MODEL);
// Append source character to destination item.
// This is the actual ansi escape code.
modify_item(p0, p5, (void*) WIDE_CHARACTER_TEXT_STATE_CYBOI_TYPE, (void*) FALSE_BOOLEAN_STATE_CYBOI_MODEL, (void*) PRIMITIVE_STATE_CYBOI_MODEL_COUNT, *NULL_POINTER_STATE_CYBOI_MODEL, (void*) VALUE_PRIMITIVE_STATE_CYBOI_NAME, (void*) TRUE_BOOLEAN_STATE_CYBOI_MODEL, (void*) APPEND_MODIFY_LOGIC_CYBOI_FORMAT);
// Set loop break flag.
// All values have been received, so that the loop can be left now.
copy_integer(p2, (void*) TRUE_BOOLEAN_STATE_CYBOI_MODEL);
} else if (*esc == *TRUE_BOOLEAN_STATE_CYBOI_MODEL) {
// The escape character ESC was received before.
// This might be the beginning of an ansi escape code.
// Reset escape character flag.
copy_integer(p3, (void*) FALSE_BOOLEAN_STATE_CYBOI_MODEL);
if (*c == *((wint_t*) LEFT_SQUARE_BRACKET_UNICODE_CHARACTER_CODE_MODEL)) {
// The escape character ESC received before
// is followed by an opening square bracket [.
// This is the beginning of an ansi escape code.
// Set ansi escape code flag.
copy_integer(p4, (void*) TRUE_BOOLEAN_STATE_CYBOI_MODEL);
// Append source character to destination item.
modify_item(p0, p5, (void*) WIDE_CHARACTER_TEXT_STATE_CYBOI_TYPE, (void*) FALSE_BOOLEAN_STATE_CYBOI_MODEL, (void*) PRIMITIVE_STATE_CYBOI_MODEL_COUNT, *NULL_POINTER_STATE_CYBOI_MODEL, (void*) VALUE_PRIMITIVE_STATE_CYBOI_NAME, (void*) TRUE_BOOLEAN_STATE_CYBOI_MODEL, (void*) APPEND_MODIFY_LOGIC_CYBOI_FORMAT);
} else {
// The escape character ESC received before
// is followed by another, second character
// which is NOT an opening square bracket.
// This is NOT going to be an ansi escape code sequence.
// Unread this character so that it may be
// processed once more later on.
ungetwc(*c, f);
// Set loop break flag.
copy_integer(p2, (void*) TRUE_BOOLEAN_STATE_CYBOI_MODEL);
}
} else if (*c == *((wint_t*) ESCAPE_UNICODE_CHARACTER_CODE_MODEL)) {
// The escape character ESC was received.
// This might be the beginning of an ansi escape code.
// Set escape character flag.
copy_integer(p3, (void*) TRUE_BOOLEAN_STATE_CYBOI_MODEL);
// Copy source character to destination character array.
modify_item(p0, p5, (void*) WIDE_CHARACTER_TEXT_STATE_CYBOI_TYPE, (void*) FALSE_BOOLEAN_STATE_CYBOI_MODEL, (void*) PRIMITIVE_STATE_CYBOI_MODEL_COUNT, *NULL_POINTER_STATE_CYBOI_MODEL, (void*) VALUE_PRIMITIVE_STATE_CYBOI_NAME, (void*) TRUE_BOOLEAN_STATE_CYBOI_MODEL, (void*) APPEND_MODIFY_LOGIC_CYBOI_FORMAT);
} else {
// No special characters have been found.
// So this is a normal source character
// that is just copied to the destination.
// Copy source character to destination character array.
modify_item(p0, p5, (void*) WIDE_CHARACTER_TEXT_STATE_CYBOI_TYPE, (void*) FALSE_BOOLEAN_STATE_CYBOI_MODEL, (void*) PRIMITIVE_STATE_CYBOI_MODEL_COUNT, *NULL_POINTER_STATE_CYBOI_MODEL, (void*) VALUE_PRIMITIVE_STATE_CYBOI_NAME, (void*) TRUE_BOOLEAN_STATE_CYBOI_MODEL, (void*) APPEND_MODIFY_LOGIC_CYBOI_FORMAT);
// CAUTION! Do NOT set loop break flag here.
// More than just one character might have to be
// received in a sequence, e.g. an ansi escape code.
// In this case, only a WEOF will break the loop.
}
} else {
// Set loop break flag.
copy_integer(p2, (void*) TRUE_BOOLEAN_STATE_CYBOI_MODEL);
}
Is the termios c_cc[VMIN] value possibly cached and not read from shared memory?
Find the project and all source code here: https://savannah.nongnu.org/svn/?group=cybop
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