demangle(3C)
dem, demangle - Demangle C++ external names to a readable format
As shipped in IRIX 6.5.5. Added in IRIX 6.5.5.
NAME dem, demangle - Demangle C++ external names to a readable format SYNOPSIS #include <dem.h> cc [flag ...] file ... -lmangle [library ...] typedef struct DEMARG DEMARG; typedef struct DEMCL DEMCL; typedef struct DEM DEM; int demangle(const char *in, char *out); int dem(char *s, DEM *p, char *buf); void dem_printcl(DEMCL *p, char *buf); void dem_printarg(DEMARG *p, char *buf, int f); void dem_printarglist(DEMARG *p, char *buf, int sv); int dem_print(DEM *p, char *buf); void dem_printfunc(DEM *dp, char *buf); IMPLEMENTATION IRIX systems DESCRIPTION dem and demangle are interfaces for user programs to demangle the mangled external names that C++ produces for functions, class members, etc. A description of the C++ mangling scheme is provided in the Annotated C++ Reference Manual (ARM). The simplest interface to the library is to call the demangle() function, as follows: int ret; char inbuf[1024]; char outbuf[MAXDBUF]; if ((ret = demangle(inbuf, outbuf)) < 0) { /* error! */ } The demangle() function will return 0 if it successfully demangled the name. If the demangle operation fails, the input string (inbuf) is copied to the output buffer (outbuf). To attain a finer level of control over the demangling operation, call the dem() function as follows: int ret; char inbuf[1024]; DEM d; char sbuf[MAXDBUF]; ret = dem(inbuf, &d, sbuf); where inbuf is the input name, d the data structure that dem() fills up, and sbuf is used as an internal buffer that the demangler uses to allocate this data structure (d will contain pointers into sbuf). Note that the first parameter to dem() is of type char *, not const char *: A call to dem() may alter its input. There is a constant MAXDBUF defined in dem.h. This is the maximum size of buffer required for an unmangled name's data structure. dem() returns -1 if there is an error, otherwise it returns 0. The <dem.h> include file has comments describing each field in the data structures. The data structures are somewhat complicated by the need to handle nested types and function arguments which themselves are function pointers with their own arguments. The following functions can be used to format this data structure: * dem_print() formats a complete demangled name from the contents of the DEM structure. * dem_printcl() formats just a class name. * dem_printfunc() format just a function name. * dem_printarg() formats a single function argument. * dem_printarglist() formats a complete function argument list. DIAGNOSTICS demangle(), dem(), and dem_print() return 0 if they succeed, and -1 if the input name is not a valid mangled name (or if there are any other error conditions, like passing in invalid arguments). EXAMPLES This particular application reads from standard input and displays the class name for each mangled name read, or "(none)" on errors and C functions/data. #include <stdio.h> #include <dem.h> main() { char sbuf[MAXDBUF]; DEM d; int ret; char buf[1024]; char buf2[1024]; while (gets(buf) != NULL) { ret = dem(buf, &d, sbuf); if (ret || d.cl == NULL) { printf("%s --> (none)\n", buf); } else { dem_printcl(d.cl, buf2); printf("%s --> %s\n", buf, buf2); } } } TYPENAMES The demangler handles mangled class typenames, whether they are simple, nested, or template classes. For example: A__pt__2_i --> A<int> __Q2_1A1B --> A::B LOCAL VARIABLES The demangler also handles local variables of the following form: __nnnxxx For example: __2x --> x BUGS AND AMBIGUITIES 1. "signed" and "volatile" encodings are not handled. 2. The encoding for nested classes as mentioned in the ARM is handled slightly differently in cfront; there is a "_" after the digit after the "Q". 3. A nested class starting with "Q" sometimes has the length encoded before it; the demangler handles either case. 4. The "Tnn" and "Nnnn" notations mentioned in the ARM are not fully supported. It is assumed that the number of the designated argument is less than or equal to 9. So, if you have 11 or more arguments, and you want to repeat argument 10 or greater, the demangler will reject the encoded name. 5. All literal arguments to templates are assumed to be const. For example, the non-const literal value 37 is encoded as Ci. 6. Some compilers will add a gratuitous "_" before external names. 7. The grammar allows class names up to 999 characters. This is considered important for handling templates. GRAMMAR FOR EXTERNAL NAMES start --> name ################# COMPLETE NAMES ################# name --> sti | std | ptbl | func | data | vtbl | cname3 | local sti --> "__sti" "__" id std --> "__std" "__" id ptbl --> "__ptbl_vec" "__" id func --> "__op" arg funcpost | id funcpost funcpost --> "__" funcpost2 | "__" cname funcpost2 funcpost2 --> csv "F" arglist csv --> "" | "C" | "S" | "V" data --> id | id "__" cname vtbl --> "__vtbl" "__" cname local --> "__" num regid ################# CLASS NAMES ################# cname --> cname2 | nest nest --> "Q" digit "_" cnamelist cnamelist --> cname2 | cnamelist cname2 cname2 --> cnlen cnid cname3 --> cnid | "__" nest cnlen --> digit | digit digit | digit digit digit cnid --> id | id "__pt__" cnlen "_" arglist ################# ARGUMENT LISTS ################# arglist --> arg | arglist arg arg --> modlist arg2 | "X" modlist arg2 lit modlist --> mod | modlist mod mod --> "" | "U" | "C" | "V" | "S" | "P" | "R" | arr | mptr arr --> "A" num "_" mptr --> "M" cname arg2 --> fund | cname | funcp | repeat1 | repeat2 fund --> "v" | "c" | "s" | "i" | "l" | "f" | "d" | "r" | "e" funcp --> "F" arglist "_" arg repeat1 --> "T" digit | "T" digit digit repeat2 --> "N" digit digit | "N" digit digit digit lit --> litnum | zero | litmptr | cnlen id | sptr litnum --> "L" digit lnum | "L" digit digit "_" lnum litmptr --> "LM" num "_" litnum "_" cnlen id lnum --> num | "n" num sptr --> cnlen id "__" cname zero --> 0 ################# LOW LEVEL STUFF ################# digit --> 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 id --> special | regid special --> "__ct" | "__pp" # etc. regid --> letter | letter restid restid --> letter | digit | restid letter | restid digit letter --> "A"-"Z" | "a" - "z" | "_" num --> digit | num digit SEE ALSO This man page is available only online.