Update help message defaults based on config.h

This change moves default value macros from config.c to config.h and
updates the help message in main.c to use these macros. This reduces
maintenance load by ensuring that the help message always reflects
the actual default values used in the code.

Resolves #150

Author: fangfufu

CHANGELOG.md

@@ -21,6 +21,11 @@ and this project adheres to
   ([3a53c40](https://github.com/fangfufu/httpdirfs/commit/3a53c40))
   (https://github.com/fangfufu/httpdirfs/issues/177).
 
+### Changed
+
+- Update help's default value based on `config.h`
+  (https://github.com/fangfufu/httpdirfs/issues/150).
+
 ## [1.2.8] - 2026-05-10
 
 ### Added

src/config.c

@@ -3,22 +3,6 @@
 #include "log.h"
 #include <stddef.h>
 
-/**
- * \brief The default HTTP 429 (too many requests) wait time
- */
-#define DEFAULT_HTTP_WAIT_SEC 5
-/**
- * \brief Data file block size
- * \details We set it to 1024*1024*8 = 8MiB
- */
-#define DEFAULT_DATA_BLKSZ (8 * 1024 * 1024)
-
-/**
- * \brief Maximum segment block count
- * \details This is set to 128*1024 blocks, which uses 128KB. By default,
- * this allows the user to store (128*1024)*(8*1024*1024) = 1TB of data
- */
-#define DEFAULT_MAX_SEGBC (128 * 1024)
 
 ConfigStruct CONFIG;
 

src/config.h

@@ -28,6 +28,32 @@
  */
 #define DEFAULT_REFRESH_TIMEOUT 3600
 
+/**
+ * \brief The default HTTP 429 (too many requests) wait time
+ */
+#define DEFAULT_HTTP_WAIT_SEC 5
+
+/**
+ * \brief Data file block size in MB
+ */
+#define DEFAULT_DATA_BLKSZ_MB 8
+
+/**
+ * \brief Data file block size
+ * \details We set it to 1024*1024*8 = 8MiB
+ */
+#define DEFAULT_DATA_BLKSZ (DEFAULT_DATA_BLKSZ_MB * 1024 * 1024)
+
+/**
+ * \brief Maximum segment block count
+ * \details This is set to 128*1024 blocks, which uses 128KB. By default,
+ * this allows the user to store (128*1024)*(8*1024*1024) = 1TB of data
+ */
+#define DEFAULT_MAX_SEGBC (128 * 1024)
+
+#define STR(x) #x
+#define XSTR(x) STR(x)
+
 /**
  * \brief Operation modes
  */

src/main.c

@@ -440,23 +440,24 @@ HTTPDirFS options:\n\
                             specified with `--cache-location`, if the option is\n\
                             seen first. Then exit in either case.\n\
         --cacert            Certificate authority for the server\n\
-        --dl-seg-size       Set cache download segment size, in MB (default: 8)\n\
+        --dl-seg-size       Set cache download segment size, in MB (default: " XSTR(
+                        DEFAULT_DATA_BLKSZ_MB) ")\n\
                             Note: this setting is ignored if previously\n\
                             cached data is found for the requested file.\n\
         --http-header       Set one or more HTTP headers\n\
         --max-seg-count     Set maximum number of download segments a file\n\
-                            can have. (default: 128*1024)\n\
+                            can have. (default: " XSTR(DEFAULT_MAX_SEGBC) ")\n\
                             With the default setting, the maximum memory usage\n\
                             per file is 128KB. This allows caching files up\n\
                             to 1TB in size using the default segment size.\n\
         --max-conns         Set maximum number of network connections that\n\
-                            libcurl is allowed to make. (default: 10)\n\
+                            libcurl is allowed to make. (default: " XSTR(DEFAULT_NETWORK_MAX_CONNS) ")\n\
         --refresh-timeout   The directories are refreshed after the specified\n\
-                            time, in seconds (default: 3600)\n\
+                            time, in seconds (default: " XSTR(DEFAULT_REFRESH_TIMEOUT) ")\n\
         --retry-wait        Set delay in seconds before retrying an HTTP request\n\
-                            after encountering an error. (default: 5)\n\
+                            after encountering an error. (default: " XSTR(DEFAULT_HTTP_WAIT_SEC) ")\n\
         --invalid-refresh   Try refreshing invalid links when reading a directory.\n\
-        --user-agent        Set user agent string (default: \"HTTPDirFS\")\n\
+        --user-agent        Set user agent string (default: \"" DEFAULT_USER_AGENT "\")\n\
         --no-range-check    Disable the built-in check for the server's support\n\
                             for HTTP range requests\n\
         --zero-len-is-dir   If a file has a zero length, treat it as a directory\n\