Fixed reading from stdin with calc -p

CHANGES

@@ -23,6 +23,17 @@ The following are the changes from calc version 2.12.6.0 to date:
     Renamed README to README.FIRST.  Added README.md for the
     GitHub repository.
 
+    Fixed reading from standard input (stdin) when -p is given on
+    the comamnd line.  This now prints hello:
+
+	echo hello | calc -p 'stdin = files(0); print fgetline(stdin);'
+
+    Added more debugging realted to stdin when bit 4 of calc_debug
+    is set (e.g., running calc with -D16).
+
+    Updated the calc(1) man page and 'help file' to explain about
+    reading from standard input (stdin).
+
 
 The following are the changes from calc version 2.12.5.4 to 2.12.5.6:
 

Makefile.ship

@@ -2268,7 +2268,7 @@ calc.1: calc.man ${MAKE_FILE}
 	        -e 's,$${CUSTOMINCDIR},${CUSTOMINCDIR},g' \
 	        -e 's,$${CUSTOMHELPDIR},${CUSTOMHELPDIR},g' \
 	        -e 's,$${CALCRC},${CALCRC},g' < calc.man > calc.1
-	${Q} echo calc.man formed
+	${Q} echo calc.1 formed
 
 calc.usage: calc.1 ${MAKE_FILE}
 	${RM} -f $@

calc.c

@@ -110,6 +110,7 @@ main(int argc, char **argv)
 	BOOL done = FALSE;
 	BOOL havearg;
 	BOOL haveendstr;
+	BOOL stdin_closed = FALSE;
 	size_t len;
 
 	/*
@@ -483,8 +484,11 @@ main(int argc, char **argv)
 	if (havecommands) {
 		cmdbuf[cmdlen++] = '\n';
 		cmdbuf[cmdlen] = '\0';
-		if (fclose(stdin)) {
+		if (p_flag != TRUE) {
-			perror("main(): fclose(stdin) failed:");
+			if (fclose(stdin)) {
+				perror("main(): fclose(stdin) failed:");
+			}
+			stdin_closed = TRUE;
 		}
 	}
 
@@ -495,7 +499,9 @@ main(int argc, char **argv)
 	 * unbuffered mode
 	 */
 	if (u_flag) {
-		setbuf(stdin, NULL);
+		if (stdin_closed == FALSE) {
+			setbuf(stdin, NULL);
+		}
 		setbuf(stdout, NULL);
 	}
 
@@ -504,6 +510,17 @@ main(int argc, char **argv)
 	 * initialize
 	 */
 	libcalc_call_me_first();
+	if (u_flag) {
+		if (conf->calc_debug & CALCDBG_TTY) {
+			if (stdin_closed == FALSE) {
+				printf("main: stdin set to unbuffered before "
+				       "calling libcalc_call_me_first()\n");
+			} else {
+				printf("main: stdin closed before "
+				       "calling libcalc_call_me_first()\n");
+			}
+		}
+	}
 	stdin_tty = isatty(0);		/* assume stdin is on fd 0 */
 	if (conf->calc_debug & CALCDBG_TTY)
 		printf("main: stdin_tty is %d\n", stdin_tty);

calc.man

@@ -554,6 +554,40 @@ print 27! ^2	or	print 27\!^2
 .fi
 .in -5n
 
+Reading from standard input when calc is part of a pipe works
+as long as the \-p flag is given to calc.  For example, this
+will print chongo was here:
+.sp 1
+.in +5n
+.nf
+echo chongo was here | calc \-p 'print fgetline(files(0));'
+.sp 1
+.fi
+.in -5n
+.sp 1
+while this does not:
+.sp 1
+.in +5n
+.nf
+echo chongo was here | calc 'print fgetline(files(0));'
+.sp 1
+.fi
+.in -5n
+.sp 1
+nor will this print chongo was here:
+.sp 1
+.in +5n
+.nf
+echo chongo was here | calc \-i 'print fgetline(files(0));'
+.sp 1
+.fi
+.in -5n
+.sp 1
+This is because without \-p, the interactive parser, in an effort
+to parse interactive commands, flushes data on standard input.
+
+.PP
+
 \&
 .br
 CALC STARTUP FILES

help/file

@@ -50,6 +50,15 @@ Using files
 
 	    stdout = files(1);
 
+     Or for example, if you wanted to assign a file value which is
+     equivalent to stdin, you could use:
+
+	    stdout = files(0);
+
+    And for stderr:
+
+	    stderr = files(2);
+
     The 'fclose' function is used to close a file which had been opened.
     When this is done, the file value associated with the file remains
     a file value, but appears 'closed', and cannot be used in further
@@ -100,6 +109,36 @@ Using files
     single character string.  It returns the null value when end of file
     is reached.
 
+    Reading from standard input when calc is part of a pipe works
+    as long as the -p flag is given to calc.  For example, this
+    will print "chongo was here":
+
+	    echo chongo was here | calc -p 'print fgetline(files(0));'
+
+    while this does not:
+
+	    echo chongo was here | calc 'print fgetline(files(0));'
+
+    nor will this print "chongo was here":
+
+	    echo chongo was here | calc -i 'print fgetline(files(0));'
+
+    This is because without -p, the interactive parser, in an effort
+    to parse interactive commands, flushes data on standard input.
+
+    On the other hand, once interactive mode is entered, reading
+    from standard input works as expected.  For example, this works:
+
+	    $ calc
+	    C-style arbitrary precision calculator (version 2.12.6.0)
+	    Calc is open software. For license details type:  help copyright
+	    [Type "exit" to exit, or "help" for help.]
+
+	    ; str = fgetline(files(0))
+	    this text was typed into stdin
+	    ; print str
+	    this text was typed into stdin
+
     The 'printf' and 'fprintf' functions are used to print results to a
     file (which could be stdout or stderr).  The 'fprintf' function
     accepts a file variable, whereas the 'printf' function assumes the

input.c

@@ -361,6 +361,10 @@ f_pathopen(char *name, char *mode, char *pathlist, char **openpath)
 		}
 		if (*openpath == NULL) {
 			free(path);
+			if ((conf->calc_debug & CALCDBG_TTY) && ret == stdin) {
+				printf("f_pathopen: closing stdin "
+				       "on malloc return error\n");
+			}
 			fclose(ret);
 			math_error("cannot malloc return openpath buffer");
 			/*NOTREACHED*/
@@ -647,8 +651,13 @@ closeinput(void)
 		return;
 	if (cip->i_str)
 		free(cip->i_str);
-	if (cip->i_fp)
+	if (cip->i_fp) {
+		if ((conf->calc_debug & CALCDBG_TTY) && cip->i_fp == stdin) {
+			printf("closeinput: closing stdin "
+			        "at depth: %d\n", depth);
+		}
 		fclose(cip->i_fp);
+	}
 	if (cip->i_name)
 		free(cip->i_name);
 	depth--;