CINT(API)
CAUTION: Please refer to doc/ref.txt. This file is getting old.
This document describes CINT C/C++ interpreter API functions.
CINT API functions
Following functions are supplied by cint for debugging
and source code analysis purposes.
char *G__input(const char *prompt);
int G__pause();
int G__tracemode(int on_off);
int G__setbreakpoint(char *breakline,char *breakfile);
int G__stepmode(int on_off);
[anytype] G__calc(const char *expression);
[anytype] G__exec_tempfile(const char *file);
int G__loadfile(const char *file);
int G__unloadfile(const char *file);
int G__reloadfile(const char *file);
char *G__search_next_member(const char *name,int state);
void *G__what_type(const char *name,char *type,char *tagname,char *typename);
int G__lock_variable(char *varname);
int G__unlock_variable(char *varname);
G__graph(double xdata[],double ydata[],int ndata,char *title,int mode);
# char *G__input(const char *prompt);
G__input() reads keyboard input. It returns pointer to
char declared as static opject in G__pause(). So, the
returned pointer must not be freed.
main() { // example program
char *command;
while(1) {
command = G__input("input command > ");
if(strcmp(command,"exit")==0) exit();
system(command);
}
}
# int G__pause();
When G__pause() is called, interactive interface is
started. Debug commands can be used. G__pause() returns
1 if 'I' command is given. So you can repeat calling
G__pause() until 'i' input by following example.
while(G__pause()==0);
# int G__tracemode(int on_off);
G__tracemode() sets trace mode.
# int G__breakline(int line);
G__breakline() sets break point. If 0 is given as argument,
break point is cleared.
# int G__stepmode(int on_off);
G__stepmode() switchs on/off step execution mode.
# [anytype] G__calc(char *expression);
G__calc() evaluates C expression. It returns the type of
object the argument expression returns. Variables and
function calls can be used in the expression. Declara-
tion, loop and conditional statement can not be used in
the expression.
int i;
double a;
i = G__calc("1+2+3"); // returns int
a = G__calc("3.14*i"); // returns double
# [anytype] G__exec_tempfile(char *file);
G__exec_tempfile() opens temporal source file and execute
it in the current context. The tempfile can contain,
variable declaration, struct,union,enum definition.
expression, loop and control statement and cannot contain
function definition. G__exec_tempfile() executes a state-
ment or statement list surrounded by '{' , '}' and returns
the last evaluated value.
{ // example of tempfile
int i;
double ary[100];
for(i=0;i<100;i++) ary[i] = i;
}
Then in the main program, you can execute above statement
by G__exec_tempfile.
# int G__loadfile(const char *file);
G__loadfile() incrementally loads source file. If file
# int G__unloadfile(const char *file);
G__unloadfile() unloads source file. If any of the func-
tions included in the file is busy, G__unloadfile()
returns error code (-1) and won't unload it.
# int G__reloadfile(const char *file);
G__reloadfile() does G__unloadfile() and G__loadfile() at
once.
# char *G__search_next_member(const char *name,int state);
G__search_next_member() searches for function and vari-
able name in current scope which start with name. state=0
must be given at the first call of G__search_next_member()
for initialization. In consequitive calls, state must be 1.
G__search_next_member() returns malloced pointer. If you
call this function, you must free() the returned pointer
afterwards.
# void *G__what_type(const char *name,char *type,char *tagname
,char *typename);
G__what_type() returns pointer and type information of
the object of name. Sufficient length of string pointer
must be given to typa,tagname and typename argument.
# int G__lock_variable(char *varname);
# int G__unlock_variable(char *varname);
(THIS CAPABILITY IS OBSOLETED IN CINT-5.14.5)
G__lock_variable() and G__unlock_variable() control
assignment locking. Assignement to specific variable can
be locked/unlocked.
# G__graph(double xdata[],double ydata[],int ndata,char *title,int mode);
G__graph() uses xgraph to plot 2 dimentinal graph. If
mode is 0, G__graph() waits for xgraph process to be ter-
minated. If mode is 1, xgraph becomes a background job. If
mode is 3, G__graph() appends x and y data to "G__graph"
file and will not invoke xgraph process.
# ERTTI (Extensive Run Time Type Identification)
Many people are interested in Cint as basement for build-
ing class browser or program analyzer. For those people,
ERTTI API which gives an access to Cint's symbol table is
a useful interface. Information about ERTTI is documented
in doc/ref.txt
# pragma compile
Source file can be partially compiled by '#pragma com-
pile' statement. In the following example, 'int globals;'
and 'func()' are compiled when they are updated. When
this program is first executed by cint, makecint is
invoked and source code surrounded by '#pragma compile'
and '#pragma endcompile' will be compiled into a dynamic
link library 'G__autocc.sl'. The G__autocc.sl is automati-
cally loaded and compiled version of 'func()' will be exe-
cuted.
This feature is only available on HP-UX 8.0 or later ver-
sion.
// #pragma disablecomppile
#pragma compile
int globals; /* this global variable is compiled */
#pragma endcompile
main(int argc,char **argv) {
func(argv[1]);
}
#pragma compile
int func(char *string)
{
/* this function is compiled and dynamically linked */
}
#pragma compile
Specifies beginning of compiled section which must be
ended by '#pragma endcompile'. Multiple compile,endcompile
pair can appear in the source code.
#pragma endcompile
Specifies end of compiled section.
#pragma disablecompile
Turn off '#pragma compile'. Pragma compile is turned on
by default. '#pragma disablecompile' must be described if
you turn off the mode.
#pragma enablecompile
Turn on '#pragma compile'.
Undeclared symbol
Cint can execute C code which includes undeclared sym-
bols. Undeclared symbols are detected and handled by
interpreter at run time. As cint detects undeclared sym-
bols, warning message is printed out and execution will be
continued.
Assigning to undeclared variable:
If assignment to undeclared variable appears, cint allo-
cates automatic variable. If assignment value is double
or float, double type variable is allocated. Otherwise,
int type variable is allocated. For example, following
program works as intended.
main() {
double dat[10];
for(i=0;i<10;i++) { /* i allocated as int */
dat[i]=i;
sum += dat[i]; /* sum allocated as double */
}
printf("sum=%g\n",sum);
}
If undeclared symbol first appears as array form, array of
appropriate size will be allocated. For example, if
'data[1][10]=3.14' appears without declaration of 'data' ,
'double data[2][11]' is allocated and 'data[1][10]=3.14'
is assigned. Array can not be expanded after the auto-
matic allocation. So, 'data[2][15]=15;' will be rejected
because array index is out of range.
main() {
data[1][10]=3.14; // double data[2][11]; data[1][10]=3.14;
data[0][3]=153.3; // OK
data[2][15]=-15.0; // rejected, array can not be expanded
}
Pointer to automatically allocated variable can not be
used. If undeclared variable appears with referencing
operator '*' or '&', these operators are ignored.
Referencing undeclared variable:
If undeclared variable is referenced, cint returns NULL
or zero as its value.
Undeclared function:
If undeclared function is called, it is simply skipped.
Parameter list will be evaluated.
main() {
int i=0;
undeclaredfunc(i++); // function call skipped
// i is 1 here because i++ was evaluated above
}
BUGS
Report bugs and requirements to cint@pcroot.cern.ch. Bugs
tend to be fixed very quickly. Any kind of comments or
messages will be appreciated.
SEE ALSO
doc/makecint.txt
AUTHOR
Masaharu Goto (cint@pcroot.cern.ch)
Copyright (c) 1995~1999 Masaharu Goto
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