X-Git-Url: https://wimlib.net/git/?p=wimlib;a=blobdiff_plain;f=include%2Fwimlib.h;h=9c8239aa0c47ff95d99b489c5e6bf614d5258a9d;hp=b7a21cf443ecb078c0b7694cfd7bc6164f828b89;hb=2373daf5bfb881b29bd2712c322c0e7c70ecc1ca;hpb=4b8dbcb1723bacdd692ea57184cb49ce3d2b7774

diff --git a/include/wimlib.h b/include/wimlib.h
index b7a21cf4..9c8239aa 100644
--- a/include/wimlib.h
+++ b/include/wimlib.h
@@ -200,6 +200,13 @@ typedef char wimlib_tchar;
 #  define WIMLIB_WIM_PATH_SEPARATOR '/'
 #  define WIMLIB_WIM_PATH_SEPARATOR_STRING "/"
 #endif
+
+#ifdef __GNUC__
+#  define _wimlib_deprecated __attribute__((deprecated))
+#else
+#  define _wimlib_deprecated
+#endif
+
 /**
  * Specifies the compression type of a WIM file.
  */
@@ -615,6 +622,97 @@ struct wimlib_capture_config {
 	size_t _prefix_num_tchars;
 };
 
+/** Set or unset the WIM header flag that marks it read-only
+ * (WIM_HDR_FLAG_READONLY in Microsoft's documentation), based on the
+ * ::wimlib_wim_info.is_marked_readonly member of the @a info parameter.  This
+ * is distinct from basic file permissions; this flag can be set on a WIM file
+ * that is physically writable.  If this flag is set, all further operations to
+ * modify the WIM will fail, except calling wimlib_overwrite() with
+ * ::WIMLIB_WRITE_FLAG_IGNORE_READONLY_FLAG specified, which is a loophole that
+ * allows you to set this flag persistently on the underlying WIM file.
+ */
+#define WIMLIB_CHANGE_READONLY_FLAG		0x00000001
+
+/** Set the GUID (globally unique identifier) of the WIM file to the value
+ * specified in ::wimlib_wim_info.guid of the @a info parameter. */
+#define WIMLIB_CHANGE_GUID			0x00000002
+
+/** Change the bootable image of the WIM to the value specified in
+ * ::wimlib_wim_info.boot_index of the @a info parameter.  */
+#define WIMLIB_CHANGE_BOOT_INDEX		0x00000004
+
+/** Change the WIM_HDR_FLAG_RP_FIX flag of the WIM file to the value specified
+ * in ::wimlib_wim_info.has_rpfix of the @a info parameter.  This flag generally
+ * indicates whether an image in the WIM has been captured with reparse-point
+ * fixups enabled.  wimlib also treats this flag as specifying whether to do
+ * reparse-point fixups by default when capturing or applying WIM images.  */
+#define WIMLIB_CHANGE_RPFIX_FLAG		0x00000008
+
+#define WIMLIB_GUID_LEN 16
+
+/** General information about a WIM file. */
+struct wimlib_wim_info {
+
+	/** Globally unique identifier for the WIM file.  Note: all parts of a
+	 * split WIM should have an identical value in this field.  */
+	uint8_t  guid[WIMLIB_GUID_LEN];
+
+	/** Number of images in the WIM.  */
+	uint32_t image_count;
+
+	/** 1-based index of the bootable image in the WIM, or 0 if no image is
+	 * bootable.  */
+	uint32_t boot_index;
+
+	/** Version of the WIM file.  */
+	uint32_t wim_version;
+
+	/** Chunk size used for compression.  */
+	uint32_t chunk_size;
+
+	/** 1-based index of this part within a split WIM, or 1 if the WIM is
+	 * standalone.  */
+	uint16_t part_number;
+
+	/** Total number of parts in the split WIM, or 1 if the WIM is
+	 * standalone.  */
+	uint16_t total_parts;
+
+	/** One of the ::wimlib_compression_type values that specifies the
+	 * method used to compress resources in the WIM.  */
+	int32_t  compression_type;
+
+	/** Size of the WIM file in bytes, excluding the XML data and integrity
+	 * table.  */
+	uint64_t total_bytes;
+
+	/** 1 if the WIM has an integrity table  */
+	uint32_t has_integrity_table : 1;
+
+	/** 1 if the WIM was created via wimlib_open_wim() rather than
+	 * wimlib_create_new_wim(). */
+	uint32_t opened_from_file : 1;
+
+	/** 1 if the WIM is considered readonly for any reason. */
+	uint32_t is_readonly : 1;
+
+	/** 1 if reparse-point fixups are supposedly enabled for one or more
+	 * images in the WIM.  */
+	uint32_t has_rpfix : 1;
+
+	/** 1 if the WIM is marked as read-only.  */
+	uint32_t is_marked_readonly : 1;
+
+	/** 1 if the WIM is part of a spanned set.  */
+	uint32_t spanned : 1;
+
+	uint32_t write_in_progress : 1;
+	uint32_t metadata_only : 1;
+	uint32_t resource_only : 1;
+	uint32_t reserved_flags : 24;
+	uint32_t reserved[9];
+};
+
 
 /*****************************
  * WIMLIB_ADD_FLAG_*
@@ -805,12 +903,24 @@ struct wimlib_capture_config {
  * WIMLIB_OPEN_FLAG_*
  ******************************/
 
-/** Verify the WIM contents against the WIM's integrity table, if present. */
+/** Verify the WIM contents against the WIM's integrity table, if present.  This
+ * causes the raw data of the WIM file, divided into 10 MB chunks, to be
+ * checksummed and checked against the SHA1 message digests specified in the
+ * integrity table.  WIMLIB_ERR_INTEGRITY is returned if there are any
+ * mismatches.  */
 #define WIMLIB_OPEN_FLAG_CHECK_INTEGRITY		0x00000001
 
-/** Do not issue an error if the WIM is part of a split WIM. */
+/** Do not issue an error if the WIM is part of a split WIM.  */
 #define WIMLIB_OPEN_FLAG_SPLIT_OK			0x00000002
 
+/** Check if the WIM is writable and return ::WIMLIB_ERR_WIM_IS_READONLY if it
+ * is not.  A WIM is considered writable only if it is writable at the
+ * filesystem level, does not have the WIM_HDR_FLAG_READONLY flag set in its
+ * header, and is not part of a spanned set.  It is not required to provide this
+ * flag to make changes to the WIM, but with this flag you get the error sooner
+ * rather than later. */
+#define WIMLIB_OPEN_FLAG_WRITE_ACCESS			0x00000004
+
 /******************************
  * WIMLIB_UNMOUNT_FLAG_*
  ******************************/
@@ -870,6 +980,12 @@ struct wimlib_capture_config {
  * deleting an image in this way. */
 #define WIMLIB_WRITE_FLAG_SOFT_DELETE			0x00000010
 
+/** With wimlib_overwrite(), allow overwriting the WIM even if the readonly flag
+ * is set in the WIM header; this can be used in combination with
+ * wimlib_set_wim_info() with the ::WIMLIB_CHANGE_READONLY_FLAG flag to actually
+ * set the readonly flag on the on-disk WIM file. */
+#define WIMLIB_WRITE_FLAG_IGNORE_READONLY_FLAG		0x00000020
+
 /******************************
  * WIMLIB_INIT_FLAG_*
  ******************************/
@@ -1022,7 +1138,8 @@ enum wimlib_error_code {
 	WIMLIB_ERR_VOLUME_LACKS_FEATURES,
 	WIMLIB_ERR_WRITE,
 	WIMLIB_ERR_XML,
-	WIMLIB_ERR_WIM_IS_MARKED_READONLY,
+	WIMLIB_ERR_WIM_IS_READONLY,
+	WIMLIB_ERR_RESOURCE_NOT_FOUND,
 };
 
 
@@ -1050,12 +1167,14 @@ enum wimlib_error_code {
  *
  * @return 0 on success; nonzero on failure.  The possible error codes are:
  *
- * @retval ::WIMLIB_ERR_SPLIT_UNSUPPORTED
- *	@a wim is part of a split WIM.
  * @retval ::WIMLIB_ERR_IMAGE_NAME_COLLISION
  *	There is already an image in @a wim named @a name.
  * @retval ::WIMLIB_ERR_NOMEM
  *	Failed to allocate the memory needed to add the new image.
+ * @retval ::WIMLIB_ERR_WIM_IS_READONLY
+ *	The WIM file is considered read-only because of any of the reasons
+ *	mentioned in the documentation for the ::WIMLIB_OPEN_FLAG_WRITE_ACCESS
+ *	flag.
  */
 extern int
 wimlib_add_empty_image(WIMStruct *wim,
@@ -1203,9 +1322,10 @@ wimlib_create_new_wim(int ctype, WIMStruct **wim_ret);
  * 	Failed to allocate needed memory.
  * @retval ::WIMLIB_ERR_READ
  * 	Could not read the metadata resource for @a image from the WIM.
- * @retval ::WIMLIB_ERR_SPLIT_UNSUPPORTED
- * 	@a wim is part of a split WIM.  Deleting an image from a split WIM is
- * 	unsupported.
+ * @retval ::WIMLIB_ERR_WIM_IS_READONLY
+ *	The WIM file is considered read-only because of any of the reasons
+ *	mentioned in the documentation for the ::WIMLIB_OPEN_FLAG_WRITE_ACCESS
+ *	flag.
  */
 extern int
 wimlib_delete_image(WIMStruct *wim, int image);
@@ -1306,9 +1426,10 @@ wimlib_delete_image(WIMStruct *wim, int image);
  * 	complete split WIM because they do not include all the parts of the
  * 	original WIM, there are duplicate parts, or not all the parts have the
  * 	same GUID and compression type.
- * @retval ::WIMLIB_ERR_SPLIT_UNSUPPORTED
- * 	@a dest_wim is part of a split WIM.  Exporting an image to a split WIM
- * 	is unsupported.
+ * @retval ::WIMLIB_ERR_WIM_IS_READONLY
+ *	@a dest_wim is considered read-only because of any of the reasons
+ *	mentioned in the documentation for the ::WIMLIB_OPEN_FLAG_WRITE_ACCESS
+ *	flag.
  */
 extern int
 wimlib_export_image(WIMStruct *src_wim, int src_image,
@@ -1502,6 +1623,10 @@ wimlib_extract_files(WIMStruct *wim,
  * @retval ::WIMLIB_ERR_READ
  * 	A unexpected end-of-file or read error occurred when trying to read data
  * 	from the WIM file associated with @a wim.
+ * @retval ::WIMLIB_ERR_RESOURCE_NOT_FOUND
+ *	One of the dentries in the image referenced a stream not present in the
+ *	WIM's lookup table (or in any of the lookup tables of the split WIM
+ *	parts).
  * @retval ::WIMLIB_ERR_SPLIT_INVALID
  * 	The WIM is a split WIM, but the parts specified do not form a complete
  * 	split WIM because they do not include all the parts of the original WIM,
@@ -1558,30 +1683,16 @@ extern void
 wimlib_free(WIMStruct *wim);
 
 /**
- * Returns the index of the bootable image of the WIM.
- *
- * @param wim
- * 	Pointer to the ::WIMStruct for a WIM file.
- *
- * @return
- * 	0 if no image is marked as bootable, or the number of the image marked
- * 	as bootable (numbered starting at 1).
+ * Deprecated in favor of wimlib_get_wim_info().
  */
 extern int
-wimlib_get_boot_idx(const WIMStruct *wim);
+wimlib_get_boot_idx(const WIMStruct *wim) _wimlib_deprecated;
 
 /**
- * Returns the compression type used in the WIM.
- *
- * @param wim
- * 	Pointer to the ::WIMStruct for a WIM file
- *
- * @return
- * 	::WIMLIB_COMPRESSION_TYPE_NONE, ::WIMLIB_COMPRESSION_TYPE_LZX, or
- * 	::WIMLIB_COMPRESSION_TYPE_XPRESS.
+ * Deprecated in favor of wimlib_get_wim_info().
  */
 extern int
-wimlib_get_compression_type(const WIMStruct *wim);
+wimlib_get_compression_type(const WIMStruct *wim) _wimlib_deprecated;
 
 /**
  * Converts a ::wimlib_compression_type value into a string.
@@ -1653,33 +1764,31 @@ wimlib_get_image_name(const WIMStruct *wim, int image);
 
 
 /**
- * Returns the number of images contained in a WIM.
- *
- * @param wim
- * 	Pointer to the ::WIMStruct for a WIM file.  It may be either a
- * 	standalone WIM or a split WIM part.
- *
- * @return
- * 	The number of images contained in the WIM file.
+ * Deprecated in favor of wimlib_get_wim_info().
+ */
+extern int
+wimlib_get_num_images(const WIMStruct *wim) _wimlib_deprecated;
+
+/**
+ * Deprecated in favor of wimlib_get_wim_info().
  */
 extern int
-wimlib_get_num_images(const WIMStruct *wim);
+wimlib_get_part_number(const WIMStruct *wim, int *total_parts_ret) _wimlib_deprecated;
 
 /**
- * Returns the part number of a WIM in a split WIM and the total number of parts
- * of the split WIM.
+ * Get basic information about a WIM file.
  *
  * @param wim
- * 	Pointer to the ::WIMStruct for a WIM file.
- * @param total_parts_ret
- * 	If non-@c NULL, the total number of parts in the split WIM (1 for
- * 	non-split WIMs) is written to this location.
- *
+ * 	Pointer to the ::WIMStruct for a WIM file.  It may be for either a
+ * 	standalone WIM or part of a split WIM.
+ * @param info
+ *	A ::wimlib_wim_info structure that will be filled in with information
+ *	about the WIM file.
  * @return
- * 	The part number of the WIM (1 for non-split WIMs)
+ *	0
  */
 extern int
-wimlib_get_part_number(const WIMStruct *wim, int *total_parts_ret);
+wimlib_get_wim_info(WIMStruct *wim, struct wimlib_wim_info *info);
 
 /**
  * Initialization function for wimlib.  Call before using any other wimlib
@@ -1758,7 +1867,7 @@ wimlib_image_name_in_use(const WIMStruct *wim, const wimlib_tchar *name);
  *
  * @return 0 on success; nonzero on error.  This function may return any value
  * returned by wimlib_open_wim() and wimlib_write() except
- * ::WIMLIB_ERR_SPLIT_UNSUPPORTED, as well as the following error code:
+ * ::WIMLIB_ERR_WIM_IS_READONLY, as well as the following error code:
  *
  * @retval ::WIMLIB_ERR_SPLIT_INVALID
  * 	The split WIMs do not form a valid WIM because they do not include all
@@ -1921,14 +2030,19 @@ wimlib_lzx_decompress(const void *compressed_data, unsigned compressed_len,
  * @retval ::WIMLIB_ERR_READ
  * 	An unexpected end-of-file or read error occurred when trying to read
  * 	data from the WIM file associated with @a wim.
+ * @retval ::WIMLIB_ERR_RESOURCE_NOT_FOUND
+ *	One of the dentries in the image referenced a stream not present in the
+ *	WIM's lookup table (or in any of the lookup tables of the split WIM
+ *	parts).
  * @retval ::WIMLIB_ERR_SPLIT_INVALID
  * 	The WIM is a split WIM, but the parts specified do not form a complete
  * 	split WIM because they do not include all the parts of the original WIM,
  * 	there are duplicate parts, or not all the parts have the same GUID and
  * 	compression type.
- * @retval ::WIMLIB_ERR_SPLIT_UNSUPPORTED
- * 	The WIM is a split WIM and a read-write mount was requested.  We only
- * 	support mounting a split WIM read-only.
+ * @retval ::WIMLIB_ERR_WIM_IS_READONLY
+ *	::WIMLIB_MOUNT_FLAG_READWRITE was specified in @a mount_flags, but @a
+ *	wim is considered read-only because of any of the reasons mentioned in
+ *	the documentation for the ::WIMLIB_OPEN_FLAG_WRITE_ACCESS flag.
  * @retval ::WIMLIB_ERR_UNSUPPORTED
  * 	Mounting is not supported, either because the platform is Windows, or
  * 	because the platform is UNIX and wimlib was compiled with @c
@@ -1950,18 +2064,7 @@ wimlib_mount_image(WIMStruct *wim,
  * 	The path to the WIM file to open.
  * @param open_flags
  * 	Bitwise OR of flags ::WIMLIB_OPEN_FLAG_CHECK_INTEGRITY and/or
- * 	::WIMLIB_OPEN_FLAG_SPLIT_OK.
- * 	<br/> <br/>
- * 	If ::WIMLIB_OPEN_FLAG_CHECK_INTEGRITY is given, the integrity table of
- * 	the WIM, if it exists, is checked, and this function will fail with an
- * 	::WIMLIB_ERR_INTEGRITY status if any of the computed SHA1 message
- * 	digests of the WIM do not exactly match the corresponding message
- * 	digests given in the integrity table.
- * 	<br/> <br/>
- * 	If ::WIMLIB_OPEN_FLAG_SPLIT_OK is given, no error will be issued if the
- * 	WIM is part of a split WIM; otherwise ::WIMLIB_ERR_SPLIT_UNSUPPORTED is
- * 	returned.  (This flag may be removed in the future, in which case no
- * 	error will be issued when opening a split WIM.)
+ * 	::WIMLIB_OPEN_FLAG_SPLIT_OK and/or ::WIMLIB_OPEN_FLAG_WRITE_ACCESS.
  *
  * @param progress_func
  * 	If non-NULL, a function that will be called periodically with the
@@ -2018,6 +2121,10 @@ wimlib_mount_image(WIMStruct *wim,
  * @retval ::WIMLIB_ERR_UNKNOWN_VERSION
  * 	A number other than 0x10d00 is written in the version field of the WIM
  * 	header of @a wim_file.  (Probably a pre-Vista WIM).
+ * @retval ::WIMLIB_ERR_WIM_IS_READONLY
+ *	::WIMLIB_OPEN_FLAG_WRITE_ACCESS was specified but the WIM file was
+ *	considered read-only because of any of the reasons mentioned in the
+ *	documentation for the ::WIMLIB_OPEN_FLAG_WRITE_ACCESS flag.
  * @retval ::WIMLIB_ERR_XML
  * 	The XML data for @a wim_file is invalid.
  */
@@ -2086,7 +2193,7 @@ wimlib_open_wim(const wimlib_tchar *wim_file,
  * @return 0 on success; nonzero on error.  This function may return any value
  * returned by wimlib_write() as well as the following error codes:
  * @retval ::WIMLIB_ERR_ALREADY_LOCKED
- * 	The WIM was going to be modifien in-place (with no temporary file), but
+ * 	The WIM was going to be modified in-place (with no temporary file), but
  * 	an exclusive advisory lock on the on-disk WIM file could not be acquired
  * 	because another thread or process has mounted an image from the WIM
  * 	read-write or is currently modifying the WIM in-place.
@@ -2096,6 +2203,10 @@ wimlib_open_wim(const wimlib_tchar *wim_file,
  * @retval ::WIMLIB_ERR_RENAME
  * 	The temporary file that the WIM was written to could not be renamed to
  * 	the original filename of @a wim.
+ * @retval ::WIMLIB_ERR_WIM_IS_READONLY
+ *	The WIM file is considered read-only because of any of the reasons
+ *	mentioned in the documentation for the ::WIMLIB_OPEN_FLAG_WRITE_ACCESS
+ *	flag.
  */
 extern int
 wimlib_overwrite(WIMStruct *wim, int write_flags, unsigned num_threads,
@@ -2264,22 +2375,10 @@ wimlib_resolve_image(WIMStruct *wim,
 		     const wimlib_tchar *image_name_or_num);
 
 /**
- * Sets which image in the WIM is marked as bootable.
- *
- * @param wim
- * 	Pointer to the ::WIMStruct for a WIM file.
- * @param boot_idx
- * 	The number of the image to mark as bootable, or 0 to mark no image as
- * 	bootable.
- * @return 0 on success; nonzero on error.
- * @retval ::WIMLIB_ERR_INVALID_IMAGE
- * 	@a boot_idx does not specify an existing image in @a wim, and it was not
- * 	0.
- * @retval ::WIMLIB_ERR_SPLIT_UNSUPPORTED
- * 	@a wim is part of a split WIM.
+ * Deprecated in favor of wimlib_set_wim_info().
  */
 extern int
-wimlib_set_boot_idx(WIMStruct *wim, int boot_idx);
+wimlib_set_boot_idx(WIMStruct *wim, int boot_idx) _wimlib_deprecated;
 
 /**
  * Changes the description of an image in the WIM.
@@ -2300,13 +2399,44 @@ wimlib_set_boot_idx(WIMStruct *wim, int boot_idx);
  * @retval ::WIMLIB_ERR_NOMEM
  * 	Failed to allocate the memory needed to duplicate the @a description
  * 	string.
- * @retval ::WIMLIB_ERR_SPLIT_UNSUPPORTED
- * 	@a wim is part of a split WIM.
+ * @retval ::WIMLIB_ERR_WIM_IS_READONLY
+ *	@a wim is considered read-only because of any of the reasons mentioned
+ *	in the documentation for the ::WIMLIB_OPEN_FLAG_WRITE_ACCESS flag.
  */
 extern int
 wimlib_set_image_descripton(WIMStruct *wim, int image,
 			    const wimlib_tchar *description);
 
+/**
+ * Set basic information about a WIM.
+ *
+ * @param wim
+ *	A WIMStruct for a standalone WIM file.
+ * @param info
+ *	A struct ::wimlib_wim_info that contains the information to set.  Only
+ *	the information explicitly specified in the @a which flags need be
+ *	valid.
+ * @param which
+ *	Flags that specify which information to set.  This is a bitwise OR of
+ *	::WIMLIB_CHANGE_READONLY_FLAG, ::WIMLIB_CHANGE_GUID,
+ *	::WIMLIB_CHANGE_BOOT_INDEX, and/or ::WIMLIB_CHANGE_RPFIX_FLAG.
+ *
+ * @return 0 on success; nonzero on failure.
+ * @retval ::WIMLIB_ERR_WIM_IS_READONLY
+ *	The WIM file is considered read-only because of any of the reasons
+ *	mentioned in the documentation for the ::WIMLIB_OPEN_FLAG_WRITE_ACCESS
+ *	flag.  However, as a special case, if you are using
+ *	::WIMLIB_CHANGE_READONLY_FLAG to unset the readonly flag, then this
+ *	function will not fail due to the readonly flag being previously set.
+ * @retval ::WIMLIB_ERR_IMAGE_COUNT
+ *	::WIMLIB_CHANGE_BOOT_INDEX was specified, but
+ *	::wimlib_wim_info.boot_index did not specify 0 or a valid 1-based image
+ *	index in the WIM.
+ */
+extern int
+wimlib_set_wim_info(WIMStruct *wim, const struct wimlib_wim_info *info,
+		    int which);
+
 /**
  * Changes what is written in the \<FLAGS\> element in the WIM XML data
  * (something like "Core" or "Ultimate")
@@ -2326,11 +2456,12 @@ wimlib_set_image_descripton(WIMStruct *wim, int image,
  * 	@a image does not specify a single existing image in @a wim.
  * @retval ::WIMLIB_ERR_NOMEM
  * 	Failed to allocate the memory needed to duplicate the @a flags string.
- * @retval ::WIMLIB_ERR_SPLIT_UNSUPPORTED
- * 	@a wim is part of a split WIM.
+ * @retval ::WIMLIB_ERR_WIM_IS_READONLY
+ *	@a wim is considered read-only because of any of the reasons mentioned
+ *	in the documentation for the ::WIMLIB_OPEN_FLAG_WRITE_ACCESS flag.
  */
-extern int wimlib_set_image_flags(WIMStruct *wim, int image,
-				  const wimlib_tchar *flags);
+extern int
+wimlib_set_image_flags(WIMStruct *wim, int image, const wimlib_tchar *flags);
 
 /**
  * Changes the name of an image in the WIM.
@@ -2353,8 +2484,9 @@ extern int wimlib_set_image_flags(WIMStruct *wim, int image,
  * 	@a image does not specify a single existing image in @a wim.
  * @retval ::WIMLIB_ERR_NOMEM
  * 	Failed to allocate the memory needed to duplicate the @a name string.
- * @retval ::WIMLIB_ERR_SPLIT_UNSUPPORTED
- * 	@a wim is part of a split WIM.
+ * @retval ::WIMLIB_ERR_WIM_IS_READONLY
+ *	@a wim is considered read-only because of any of the reasons mentioned
+ *	in the documentation for the ::WIMLIB_OPEN_FLAG_WRITE_ACCESS flag.
  */
 extern int wimlib_set_image_name(WIMStruct *wim, int image,
 				 const wimlib_tchar *name);
@@ -2623,6 +2755,10 @@ wimlib_unmount_image(const wimlib_tchar *dir,
  * 	or, the platform is Windows and either the ::WIMLIB_ADD_FLAG_UNIX_DATA
  * 	or the ::WIMLIB_ADD_FLAG_DEREFERENCE flags were specified in the @a
  * 	add_flags for an update command.
+ * @retval ::WIMLIB_ERR_WIM_IS_READONLY
+ *	The WIM file is considered read-only because of any of the reasons
+ *	mentioned in the documentation for the ::WIMLIB_OPEN_FLAG_WRITE_ACCESS
+ *	flag.
  */
 extern int
 wimlib_update_image(WIMStruct *wim,