Changes between Version 3 and Version 4 of Development FAQ

Timestamp:

Apr 27, 2007, 8:13:51 PM (17 years ago)

Author:

John Bailey

Comment:

Merging the PROGRAMMING_NOTES file into the wiki

Development FAQ

@@ -25 +25 @@
 === Is there a way that I can print something in the conversation window, but not send the message? ===
 Yes. Use purple_conv_im_write/purple_conv_chat_write.
+
+== Files and File Paths ==
+=== What do I do with `DATADIR`, `LOCALEDIR`, and `LIBDIR`? ===
+`DATADIR`, `LOCALEDIR`, and `LIBDIR` are defined as functions in the Windows build.  Therefore, doing something like this will break the Windows build:
+{{{
+   printf("File in DATADIR is: %s\n", DATADIR G_DIR_SEPARATOR_S "pic.png")
+}}}
+
+Instead, it should be:
+{{{
+   printf("File in DATADIR is: %s%s%s\n", DATADIR, G_DIR_SEPARATOR_S, "pic.png");
+}}}
+
+=== Why are files opened with mode `b`? ===
+Without this, on Windows systems the opened files will use Windows default translation (<CR><LF> for newline, for example).  This will cause errors due to newline format and the "bytes read" counts, which will be wrong when comparing the return value of `read()` to `stat()`.
+
+=== Why are there `G_DIR_SEPARATOR_S` and `G_DIR_SEPARATOR` usages everywhere? ===
+This is a matter of maintaining cross-platform compatibility.  Windows uses a backslash ("\") for directory separators in paths, while UNIX-like systems use the forward slash ("/").  Other OSes may choose to use other separators--for example, prior to Mac OS X, it was common for the directory separator on Macs to be a colon (":").  It is impractical to use preprocessor directives throughout the code to determine the path style to use, especially if a new OS were to appear and use a different directory separator.  GLib, which we already use, provides the convenient separator macro, so we use this to reduce our code complexity and maintain cross-platform portability.
+
+== General ==
+=== What should I do to get the contents of an environment variable? ==
+Use `g_getenv()`.
+
+=== Should I use `snprintf()` or `vsnprintf()`? ===
+No.  Use the GLib wrapper functions instead.  They are `g_snprintf()` and `g_vsnprintf`.
+
+== Headers ==
+=== Why is win32dep.h causing problems for me? ===
+You need to make sure it is the last header you include if you need to include it.  Not doing so is asking for problems.
+
+== Plugins and Protocols ==
+=== How should I handle global variables? ===
+Use `G_MODULE_IMPORT` for any global variable located outside your dynamic library.  Not doing this will cause "Memory Access Violation" errors on Windows systems.
+
+=== What should I do for "exported" functions? ===
+If your plugin has functions that are to be accessed from outside the scope of its file (.dll or .so), `G_MODULE_EXPORT` those functions.