Change help texts to print to stdout (closes #2542)

include/term_ctl.h

@@ -95,9 +95,9 @@ int term_printf(void *ctx, _Printf_format_string_ const char *format, ...)
  *   "quoted"
  *   'quoted'
  */
-int term_help_printf(_Printf_format_string_ char const *format, ...)
+int term_help_fprintf(FILE *fp, _Printf_format_string_ char const *format, ...)
 #if defined(__GNUC__) || defined(__clang__)
-        __attribute__((format(printf, 1, 2)))
+        __attribute__((format(printf, 2, 3)))
 #endif
         ;
 
@@ -108,10 +108,10 @@ int term_help_printf(_Printf_format_string_ char const *format, ...)
 int term_puts(void *ctx, const char *buf);
 
 /**
- * Like 'term_help_printf()', but no var-arg format.
+ * Like 'term_help_fprintf()', but no var-arg format.
  * Simply takes a 0-terminated buffer.
  */
-int term_help_puts(void *ctx, const char *buf);
+int term_help_fputs(void *ctx, const char *buf, FILE *fp);
 
 /**
  * Change the default color map.

src/rtl_433.c

@@ -133,7 +133,7 @@ static void print_version(void)
 _Noreturn
 static void usage(int exit_code)
 {
-    term_help_printf(
+    term_help_fprintf(exit_code ? stderr : stdout,
             "Generic RF data receiver and decoder for ISM band devices using RTL-SDR and SoapySDR.\n"
             "\nUsage:\n"
             "\t\t= General options =\n"
@@ -196,21 +196,23 @@ static void help_protocols(r_device *devices, unsigned num_devices, int exit_cod
     char disabledc;
 
     if (devices) {
-        term_help_printf("\t\t= Supported device protocols =\n");
+        FILE *fp = exit_code ? stderr : stdout;
+        term_help_fprintf(fp,
+                "\t\t= Supported device protocols =\n");
         for (i = 0; i < num_devices; i++) {
             disabledc = devices[i].disabled ? '*' : ' ';
             if (devices[i].disabled <= 2) // if not hidden
-                fprintf(stderr, "    [%02u]%c %s\n", i + 1, disabledc, devices[i].name);
+                fprintf(fp, "    [%02u]%c %s\n", i + 1, disabledc, devices[i].name);
         }
-        fprintf(stderr, "\n* Disabled by default, use -R n or a conf file to enable\n");
+        fprintf(fp, "\n* Disabled by default, use -R n or a conf file to enable\n");
     }
     exit(exit_code);
 }
 
 _Noreturn
 static void help_device_selection(void)
 {
-    term_help_printf(
+    term_help_fprintf(stdout,
             "\t\t= Input device selection =\n"
 #ifdef RTLSDR
             "\tRTL-SDR device driver is available.\n"
@@ -236,7 +238,7 @@ static void help_device_selection(void)
 _Noreturn
 static void help_gain(void)
 {
-    term_help_printf(
+    term_help_fprintf(stdout,
             "\t\t= Gain option =\n"
             "  [-g <gain>] (default: auto)\n"
             "\tFor RTL-SDR: gain in dB (\"0\" is auto).\n"
@@ -248,7 +250,7 @@ static void help_gain(void)
 _Noreturn
 static void help_device_mode(void)
 {
-    term_help_printf(
+    term_help_fprintf(stdout,
             "\t\t= Input device run mode =\n"
             "  [-D restart | pause | quit | manual] Input device run mode options.\n"
             "\tSupported input device run modes:\n"
@@ -263,7 +265,7 @@ static void help_device_mode(void)
 _Noreturn
 static void help_output(void)
 {
-    term_help_printf(
+    term_help_fprintf(stdout,
             "\t\t= Output format option =\n"
             "  [-F log|kv|json|csv|mqtt|influx|syslog|trigger|null] Produce decoded output in given format.\n"
             "\tWithout this option the default is LOG and KV output. Use \"-F null\" to remove the default.\n"
@@ -289,7 +291,7 @@ static void help_output(void)
 _Noreturn
 static void help_tags(void)
 {
-    term_help_printf(
+    term_help_fprintf(stdout,
             "\t\t= Data tags option =\n"
             "  [-K FILE | PATH | <tag> | <key>=<tag>] Add an expanded token or fixed tag to every output line.\n"
             "\tIf <tag> is \"FILE\" or \"PATH\" an expanded token will be added.\n"
@@ -310,7 +312,7 @@ static void help_tags(void)
 _Noreturn
 static void help_meta(void)
 {
-    term_help_printf(
+    term_help_fprintf(stdout,
             "\t\t= Meta information option =\n"
             "  [-M time[:<options>]|protocol|level|noise[:<secs>]|stats|bits] Add various metadata to every output line.\n"
             "\tUse \"time\" to add current date and time meta data (preset for live inputs).\n"
@@ -336,7 +338,7 @@ static void help_meta(void)
 _Noreturn
 static void help_read(void)
 {
-    term_help_printf(
+    term_help_fprintf(stdout,
             "\t\t= Read file option =\n"
             "  [-r <filename>] Read data from input file instead of a receiver\n"
             "\tParameters are detected from the full path, file name, and extension.\n\n"
@@ -358,7 +360,7 @@ static void help_read(void)
 _Noreturn
 static void help_write(void)
 {
-    term_help_printf(
+    term_help_fprintf(stdout,
             "\t\t= Write file option =\n"
             "  [-w <filename>] Save data stream to output file (a '-' dumps samples to stdout)\n"
             "  [-W <filename>] Save data stream to output file, overwrite existing file\n"

src/term_ctl.c

@@ -403,14 +403,17 @@ int term_printf(void *ctx, _Printf_format_string_ char const *format, ...)
     return len;
 }
 
-int term_help_puts(void *ctx, char const *buf)
+int term_help_fputs(void *ctx, char const *buf, FILE *fp)
 {
     char const *p = buf;
     int i, len, buf_len, color, state = 0, set_color = -1, next_color = -1;
-    FILE *fp;
+    if (!fp) {
+        fp = stderr;
+    }
 
-    if (!ctx)
-        return fprintf(stderr, "%s", buf);
+    if (!ctx) {
+        return fprintf(fp, "%s", buf);
+    }
 
 #ifdef _WIN32
     console_t *console = (console_t *)ctx;
@@ -419,9 +422,6 @@ int term_help_puts(void *ctx, char const *buf)
     fp = (FILE *)ctx;
 #endif
 
-    if (!fp)
-        fp = stderr;
-
     buf_len = (int)strlen(buf);
     for (i = len = 0; *p && i < buf_len; i++, p++) {
         if (*p == '~') {
@@ -490,15 +490,15 @@ int term_help_puts(void *ctx, char const *buf)
     return len;
 }
 
-int term_help_printf(_Printf_format_string_ char const *format, ...)
+int term_help_fprintf(FILE *fp, _Printf_format_string_ char const *format, ...)
 {
     int len;
     va_list args;
     char buf[4000];
 
     va_start(args, format);
 
-    void *term = term_init(stderr);
+    void *term = term_init(fp);
     if (!term_has_color(term)) {
         term_free(term);
         term = NULL;
@@ -507,7 +507,7 @@ int term_help_printf(_Printf_format_string_ char const *format, ...)
     // Terminate first in case a buggy '_MSC_VER < 1900' is used.
     buf[sizeof(buf) - 1] = '\0';
     vsnprintf(buf, sizeof(buf) - 1, format, args);
-    len = term_help_puts(term, buf);
+    len = term_help_fputs(term, buf, fp);
 
     term_free(term);