diff options
Diffstat (limited to 'doc')
-rw-r--r-- | doc/README.developer | 23 |
1 files changed, 8 insertions, 15 deletions
diff --git a/doc/README.developer b/doc/README.developer index e4f7df3cfb..adb07fc191 100644 --- a/doc/README.developer +++ b/doc/README.developer @@ -1004,7 +1004,7 @@ FIELDBASE BASE_NONE, BASE_DEC, BASE_HEX, BASE_OCT, BASE_DEC_HEX, BASE_HEX_DEC, BASE_RANGE_STRING FIELDCONVERT VALS(x), RVALS(x), TFS(x), NULL BITMASK Usually 0x0 unless using the TFS(x) field conversion. -FIELDDESCR A brief description of the field. +FIELDDESCR A brief description of the field, or NULL. PARENT_SUBFIELD Lower level protocol field used for lookup, i.e. "tcp.port" ID_VALUE Lower level protocol field value that identifies this protocol For example the TCP or UDP port number @@ -2463,10 +2463,10 @@ Example: (from the scsi dissector) ... { &hf_scsi_inq_peripheral, {"Peripheral", "scsi.inquiry.preipheral", FT_UINT8, BASE_HEX, - NULL, 0, "", HFILL}}, + NULL, 0, NULL, HFILL}}, { &hf_scsi_inq_qualifier, {"Qualifier", "scsi.inquiry.qualifier", FT_UINT8, BASE_HEX, - VALS (scsi_qualifier_val), 0xE0, "", HFILL}}, + VALS (scsi_qualifier_val), 0xE0, NULL, HFILL}}, ... Which provides very pretty dissection of this one byte bitmask. @@ -2495,15 +2495,8 @@ table handles all possible values of the size of 'val'", not "the protocol spec says it has to be" - protocol specs do not prevent invalid packets from being put onto a network or into a purported packet capture file), you must check whether 'match_strval()' returns NULL, and arrange -that its return value not be dereferenced if it's NULL. In particular, -don't use it in a call to generate a COL_INFO line for a frame such as - - col_add_fstr(COL_INFO, ", %s", match_strval(val, table)); - -unless is it certain that 'val' is in 'table'. - -'val_to_str()' can be used to generate a string for values not found in -the table: +that its return value not be dereferenced if it's NULL. 'val_to_str()' +can be used to generate a string for values not found in the table: gchar* val_to_str(guint32 val, const value_string *vs, const char *fmt) @@ -2512,9 +2505,9 @@ If the value 'val' is found in the 'value_string' table pointed to by 'vs', 'val_to_str' will return the corresponding string; otherwise, it will use 'fmt' as an 'sprintf'-style format, with 'val' as an argument, to generate a string, and will return a pointer to that string. -(Currently, it has three 64-byte static buffers, and cycles through -them; this permits the results of up to three calls to 'val_to_str' to -be passed as arguments to a routine using those strings.) +You can use it in a call to generate a COL_INFO line for a frame such as + + col_add_fstr(COL_INFO, ", %s", val_to_str(val, table, "Unknown %d")); 1.7.2 match_strrval and rval_to_str. |