Moved termios magic out of demo.c into termkey.c where it belongs

demo.c

@@ -1,24 +1,10 @@
 #include <stdio.h>
 #include <stdlib.h>
-#include <termios.h>
 #include <unistd.h>
 
 #include "termkey.h"
 
 int main(int argc, char *argv[]) {
-  struct termios termios;
-
-  if(tcgetattr(0, &termios)) {
-    perror("ioctl(TCIOGETS)");
-    exit(1);
-  }
-
-  int old_lflag = termios.c_lflag;
-  termios.c_iflag &= ~(IXON|INLCR|ICRNL);
-  termios.c_lflag &= ~(ICANON|ECHO|ISIG);
-
-  tcsetattr(0, TCSANOW, &termios);
-
   termkey_t *tk = termkey_new(0, 0);
 
   termkey_result ret;
@@ -44,8 +30,5 @@ int main(int argc, char *argv[]) {
       break;
   }
 
-  termios.c_lflag = old_lflag;
+  termkey_destroy(tk);
-  tcsetattr(0, TCSANOW, &termios);
-
-  termkey_free(tk);
 }

termkey.c

@@ -4,6 +4,7 @@
 #include <poll.h>
 #include <unistd.h>
 #include <string.h>
+#include <termios.h>
 
 #include <stdio.h>
 
@@ -21,6 +22,9 @@ struct termkey {
   size_t buffcount; // NUMBER of entires valid in buffer
   size_t buffsize; // Total malloc'ed size
 
+  struct termios restore_termios;
+  char restore_termios_valid;
+
   int waittime; // msec
 
   char   is_closed;
@@ -78,6 +82,8 @@ termkey_t *termkey_new_full(int fd, int flags, size_t buffsize, int waittime)
   tk->buffcount = 0;
   tk->buffsize  = buffsize;
 
+  tk->restore_termios_valid = 0;
+
   tk->waittime = waittime;
 
   tk->is_closed = 0;
@@ -181,6 +187,19 @@ termkey_t *termkey_new_full(int fd, int flags, size_t buffsize, int waittime)
   termkey_register_csifunc(tk, TERMKEY_SYM_F19,      33, "F19");
   termkey_register_csifunc(tk, TERMKEY_SYM_F20,      34, "F20");
 
+  if(!(flags & TERMKEY_FLAG_NOTERMIOS)) {
+    struct termios termios;
+    if(tcgetattr(fd, &termios) == 0) {
+      tk->restore_termios = termios;
+      tk->restore_termios_valid = 1;
+
+      termios.c_iflag &= ~(IXON|INLCR|ICRNL);
+      termios.c_lflag &= ~(ICANON|ECHO|ISIG);
+
+      tcsetattr(fd, TCSANOW, &termios);
+    }
+  }
+
   return tk;
 }
 
@@ -198,6 +217,14 @@ void termkey_free(termkey_t *tk)
   free(tk);
 }
 
+void termkey_destroy(termkey_t *tk)
+{
+  if(tk->restore_termios_valid)
+    tcsetattr(tk->fd, TCSANOW, &tk->restore_termios);
+
+  termkey_free(tk);
+}
+
 void termkey_setwaittime(termkey_t *tk, int msec)
 {
   tk->waittime = msec;

termkey.h

@@ -115,10 +115,12 @@ enum {
   TERMKEY_FLAG_CONVERTKP   = 0x02, // Convert KP codes to regular keypresses
   TERMKEY_FLAG_RAW         = 0x04, // Input is raw bytes, not UTF-8
   TERMKEY_FLAG_UTF8        = 0x08, // Input is definitely UTF-8
+  TERMKEY_FLAG_NOTERMIOS   = 0x10, // Do not make initial termios calls on construction
 };
 
 termkey_t *termkey_new(int fd, int flags);
 void       termkey_free(termkey_t *tk);
+void       termkey_destroy(termkey_t *tk);
 
 void       termkey_setwaittime(termkey_t *tk, int msec);
 int        termkey_getwaittime(termkey_t *tk);